If you want to understand the invisible, look careful at the visible. The Talmud A 'bird's eye' or rather a distant spacecraft's view of the solar system reveals an assembly of planets, terrestrial, giant and Pluto. The orbital motions are in the same sense, counter clockwise, as seen from the north of the general flattened space within which the planetary motions are confined. This state of affairs is corevolving and, more or less, coplanar. The rotations are in the same sense as the revolutions, with the strikiiig exception of Uranus whose sense of rotation is perpendicular to its plane of revolution. As time goes by, most of the planets remain fairly close to a general plane and at no time stray unduly far from it; they remain confined within a rather narrow box or disk with a large 'equatorial' extent. The most distant planet, Pluto, requires a diameter of some 80 astronomical units for the disk. One astronomical unit is the distance of the Earth to the Sun, to be more precise the length of half the major axis of the Earth's slightly elliptical orbit around the Sun, and amounts to nearly 149600000 km.

On the occasion of the International Conference on Cosmic Rays held in Kyoto in August 1979 five aged members of the cosmic ray fraternity, H. Elliot, V. L. Ginzburg, B. Peters, Y. Sekido, and J. A. Simpson met together as a dinner party devoted to the enjoyment of Japanese cuisine and reminiscences of our younger days. This pleasant occasion called to of our own age as well as some eminent seniors not present at the mind the many friends conference whose recollections would have further enriched and enlivened our evening. By the time the dinner came to an end we had agreed that the compilation of a more extensive collection of personal reminiscences would be an interesting and worthwhile undertaking. Accordingly, the next day we held an editorial meeting to draw up a list of potential authors and two of us, the present editors, started work on the project. In putting the book together our intention has been to try to capture and record through these personal accounts something of the atmosphere, the excitement and the frustrations of research in cosmic rays as experienced at first hand by some of the practi tioners in the field. It has never been our intention that it should comprise a systematic history of the subject. Neither, unfortunately, can it be a fully representative collection since practical limits to the size of the volume alone would preclude that."

Galactic Astronomy is, and for some time to come will certainly remain, one of the more important items in the astronomy curricula. There are at present a number of excellent text-books and monographs covering the whole subject or certain of its aspects. It seems however that there is not a single book where at least some of the more important problems dealt with in text-books and university courses would be presented in the form of laboratory exercises. This short series of exercises represents an attempt to fill this gap. What is, in general, the aim of such exercises? As to this point, the author fully agrees with Prof. Minnaert's opinion that "No natural science should ever be taught without practical work. Students in astronomy should have regular exercises, not so much to teach them observing skill, but mainly to bring before their eyes the reality of the concepts introduced during the lectures." This applies to Galactic Astronomy as well as to any other branch of our science.

In recent years it has become apparent that con tributions to our knowledge about the interstellar medium are made by practically all forms of astronomy ranging from radio- to gamma ray observations, and from cosmic ray measurements. It was thus thought fruitful to arrange for an interdisciplinary meeting of astron omers from the various fields of investigation, and of high energy astrophysicists. This meeting took place at Schliersee (Bavaria) from April 2 to 13, 1973. Lectures and some of the discussions held during that Advanced Study Institute are reproduced here. unfortunately, no manuscripts of the two lectures about infrared and cosmic ray observations were re ceived and these are thus not available here. However, it was thought to be more important to proceed now with the publication. The organisers are very grateful to Miss H. Eichele for her technical help during the meeting. The or ganisation of the Institute and the publication of the proceedings would have been impossible without the very great efforts and help of Mrs. M. Brunner and Mrs. D.Preis. I would also like to express my gratitude to my col leagues K.W. Michel and S. Drapatz for their many con tributions towards the success of the meeting."

The purpose of this book is to give a detailed description of the planetary nebulae including the relevant astronomical observations and their interpretation. Considerable attention is given to the evolution of these objects as well as to their physical characteristics. I t is hoped that the book be useful to both advanced research workers and to students with some background in astronomy. In this regard, the book should serve as a text as well as a reference work. The many tables included are expected to be useful for both purposes. The references are generally not included in the text except for historical purposes in an effort to improve readability. References are given at the end of each chapter together with sufficient text to describe their content. No attempt has been made to make the list of references complete; on the contrary it has generally been limited to the most recent literature on the subject which in turn refers to earlier research. Again, exceptions have been made for references of historical interest.

IAU Symposium 97, Extragalactic Radio Sources, was held at Albuquerque, New Mexico August 3-7, 1981. It was co-sponsored by IAU Commissions 28, 40, 47 and 48 and by URSI Commission J. Financial and organizational support were provided by the National Radio Astronomy Observatory, the University of New Mexico, and the National Science Foundation. A wide variety of interesting objects and phenomena can be covered under the heading "Extragalactic Radio Sources," and a diverse set of topics was in fact discussed at the symposium. Radio galaxies, quasars, Seyfert galaxies and BL Lacertids received the most attention, but normal galaxies, the galactic center, and even SS433 were also discussed. While the unifying theme of the symposium was radio emission, studies at all wavelengths--X-ray, UV, optical, IR, and radio--were included. In general, the emphasis was on individual objects and the physical processes associated with them, but there were also papers on statistical studies and cosmology. The symposium was attended by 209 scientists from 18 countries.

This publication, in two volumes, includes most of the scientific papers presented at the first meeting of the International Society for the Study of the Origin of Life (ISSOL), held on June 25-28, 1973 in Barcelona, Spain. The first volume contains the invited articles and the second volume the contributed papers, which also appear in the 1974 and 1975 issues, respectively, of the new journal Origins of Life, published by D. Reidel. A relatively large number of meetings on the subject of the origin of life have been held in different places since 1957. In terms of its organization, scope, and number and nationality of participants, the Conference celebrated last year in Barcelona closely followed the three international conferences held earlier in Moscow, U.S.S.R., 1957, Wakulla Springs, U.S.A., 1963, and Pont-a-Mousson, France, 1970. For this reason the first ISSOL meeting was also named the Ath International Conference on the Origin of Life.

X-ray astronomers discovered the diffuse gas in clusters of galaxies about 20 years ago. It was later realized that the central gas density in some clusters, and in elliptical galaxies, is so high that radiative cooling is a significant energy loss. The cooling time of the gas decreases rapidly towards the centre of the cluster or galaxy and is less than a Hubble time within the innermost few hundred kiloparsecs. This results in a cooling flow in which the gas density rises in order to maintain pressure to support the weight of the overlying gas. The rate at which mass is deposited by the flow is inferred to be several hundreds of solar masses per year in some clusters. The fraction of clusters in which cooling flows are found may exceed 50 per cent. Small flows probably occur in most normal elliptical galaxies that are not in rich clusters. The implications of this simple phenomenon are profound, for we appear to be witnessing the ongoing formation of the central galaxy. In particular, since most of the gas is undetected once it cools below about 3 million K, it appears to form dark matter. There is no reason why it should be detectable with current techniques if each cooling proton only recombines once and the matter condenses into objects of low mass.

Ptolemy's Almagest shares with Euclid's Elements the glory of being the scientific text longest in use. From its conception in the second century up to the late Renaissance, this work determined astronomy as a science. During this time the Almagest was not only a work on astronomy; the subject was defined as what is described in the Almagest. The cautious emancipation of the late middle ages and the revolutionary creation of the new science in the 16th century are not conceivable without reference to the Almagest. This text lifted European astronomy to the high standard of knowledge on which the new science flourished. Before, the Ptolemaic models of the orbits of the sun, the moon, and the planets had been refined by Arabic astronomers. They provided the structural elements with which Copernicus and Kepler ushered in the era of modern astronomy. The Almagest survived the destruction of its epicyclic representation of the planetary orbits in the conceptual traces left behind in the theories of its successors. The clear separation of the sidereal from the tropical year, the celestial coordinate systems, the concepts of time, the forms of the constellations, and brightness classifications of celestial objects are, among many other things, still part of the astronomical canon even today.

M. M. Shapiro and J. P. Wefel AN OVERVIEW OF COSMIC RAY RESEARCH: COMPOSITION, ACCELERATION AND PROPAGATION J. P. Wefel PROPAGATION AND TRANSFOR'1ATIONS OF cosme RAYS: 41 FROM SOURCES TO EARTH R. Silberberg, C. H. Tsao, J. R. Letaw and M. M. Shapiro 71 ULTRA HEAVY NUCLEI IN THE COSMIC RADIATION W. R. Binns GALACTIC COSMIC RAY HYDROGEN AND HELIUM 91 J. J. Beatty COSMIC RAYS OF THE HIGHEST ENERGIES 97 J. Szabelski STARS AND COSMIC RAYS 105 I. COOL STARS T. Montmerle STARS AND COSMIC RAYS 131 II. HOT STARS T. Montmerle ON THE POSSIBLE CONTRIBUTION OF WC STARS TO ISOTOPIC 153 ANOMALIES IN COSMIC RAYS AND METEORITES J. B. Blake and D. S. P. Dearborn GAMMA-RAY VIEWS ON THE GALACTIC COSMIC-RAY DISTRIBUTION 163 H. Bloemen VlIl RADIO ASTRONOMY AND COSMIC RAYS 175 K. W. Weiler PARTICLE ACCELERATION IN GALACTIC SUPERNOVA REMNANTS 205 D. A. Green PULSARS AS COSMIC RAY PARTICLE ACCELERATORS -- NEW RESULTS 215 ON THE DYNAMICS OF PROTONS IN VACUUM FIELDS K. o. Thie1heim CONDITIONS FOR ACCELERATION OF SUPER-HIGH ENERGY COSMIC RAYS 227 IN ACTIVE GALACTIC NUCLEI W. H. Sorrell COSMIC RAYS AND A STABLE HYDROSTATIC EQUILIBRIUM OF THE GALAXY 235 H. B10emen VRE AND URE GAMMA P Y OBSERVATIONS BY GROUND BASED 241 DETECTORS W. Stamm 15 HADRON AND MUON COMPONENTS IN PHOTON SHOWERS AT 10 eV 255 Ch. P. Vankov and J. N. Stamenov MONOPOLES, MUONS, NEUTRINOS AND CYGNUS X-3 261 M. L. Cherry, S. Corbato, D. Kieda, K. Lande, and C. K.

This volume contains the papers and discussions at IAU Colloquium No. 21 on Variable Stars in Globular Clusters and in Related Systems held in Toronto on the 29th, 30th and 31st August 1972. It was the intention of the organizers that this meeting should honour the life long work in this field of Professor Helen Sawyer Hogg. She has been continuously active in observational research on variables in globular clusters for 46 years and her catalogues and bibliographies as well as her research papers, review articles and IA U reports as chairman of the committee on variable stars in clusters are of fundamental importance to all workers in this field. The scope of the colloquium covered both observational and theoretical aspects of the problem, including the relationship of variables to non-variable cluster members, the position of the variables in the HR diagram and their importance for problems of stellar evolution, empirical data on the variables, periods and period changes, and the relevant parts of pulsation theory. The meeting was particularly successful in bringing together observers and theorists. It will have achieved its object if it has shown both observers and theorists which are the problems most suitable for attack at the present time. The meeting clearly demonstrated the great importance of research on variables in globular clusters and related systems for our understanding both of stellar evolution and stellar pulsation.

The idea to hold a conference on the Evolution of Close-Binary X-ray sources grew in the summer of 1984. At that time we were hoping that some new results would be harvested in the months to come which would stimulate further work. We were particularly looking towards the Euro pean X-ray Observatory, EXOSAT, for new contributions. How lucky we were; quite unexpected developments took place. Just prior to the conference, quasi-periodic oscillations (now known as QPO) were discovered in three bright low-mass X-ray binaries: GX 5-1, Sco X-1, and Cyg X-2. They played an important role at the meeting. The possibility that QPOs imply a neutron star magnetic dipole field, and a neutron star rotation period in the millisecond range, received a lot of attention. This is not surprising, as it lends support to the idea, suggested earlier, that the 6-msec binary radio pulsar PSR 1953+29 evolved from a stage in which it was a bright low-mass X-ray binary. There was special interest in the possibility of white dwarf collapse into a neutron star. This is a. particularly attractive way to form the bright low-mass X-ray binaries, often referred to as galactic bulge sources. It would allow for the possibility of a very young neutron star in a very old binary system. The relatively high magnetic fields that one could infer from QPO could then be explained."

The idea of holding this workshop on "The Jllilky Way" arose at the conference dinner of a meeting on "Regions of Recent Star Formation" held at Penticton in June 1981. Leo Blitz (now at the University of Maryland) and I decided that there was a need, and agreed that we would organize one in Vancouver in the Spring of 1982. The purpose of the workshop was to have an intensive exchange of ideas between some of the most active workers in the field regarding the recent work which has been significantly changing our concepts of the Milky Way. To achieve this we limited the number of participants, and planned the program so that there was ample time for discussion. The meeting appeared to work very well, both scientifically and socially, and this volume contains 50 of the 55 papers that were The discussion was very lengthy, but since the papers were presented. written up after the meeting many of the points raised have been in the publications, and it seems pointless to reproduce it incorporated here. Leo and I would like to thank the many people who helped to make the meeting a success: at UBC) and Frank J. Kerr (Provost of MPSE C.V. Finnegan (Dean of Science at the University of Maryland) who welcomed the participants on behalf of the sponsoring Universities. Bart Bok who opened the scientific proceedings, and Maarten Schmidt who gave the closing summary.

The first helium star was discovered in 1942, the first scientific meeting on the subject, however, took place in 1985. The meeting was hence long overdue for, in the meantime, a substantial amount of material had been accumulated by a rather small, but active scientific community. Hence, it appeared necessary to review the field in order to define the subject, assess its present status and discuss future developments. Hydrogen deficiency is a widespread phenomenon, occurring in a large variety of stellar and nonstellar objects. It can be readily detected in B stars as these exhibit both hydrogen and helium lines, if the elements are present in appreciable amounts. It becomes less manifest in cool stars, where the temperature is too low to excite helium and where one has to devise indirect methods for proving hydrogen deficiency. Clearly, it was not possible to discuss the whole complex of hydrogen deficiency, i.e. in both stars and diffuse matter, but rather to concentrate on the issue of helium stars.

The International Association of Geochemistry and Cosmochemistry was organized in 1967, and held its first meeting at UNESCO Headquartels that year in association with its symposium on The Origin and Distribution of the Elements'. The Association is a member of the International Union uf Geological Sciences, and holds regular meetings at the time of the I nternatlOnal Geological Congresses, the last of which was held in Montreal, in August. 1972. The IAGC was organized to coordinate activities on an international scale in a wide variety of branches of geochemistry. Its activities are carried on through Commissions and Working Groups, and by means of symposia and other international activities. It has national, corporate, and individual members. One of the first actions taken by the Council of the AGC when it met in 1967 was to establish an initial set of Working Groups to commence the activity of the organization. Among these Working Groups was one on Extraterrestrial Chemistry, established under the chairmanship of the writer. This Working Group recognized that its basic concern with the chemical composition of cosmic systems was a problem with ramifications in many fields in addition to geochemistry. The other scien tific disciplines which are involved include physics, astronomy and astrophysics, and geophysics. The Working Group thus included scientists in these disciplines from the beginning; many of the scientists had already participated in the first symposium of the IAGe. The Working Group has recently been elevated to the status of a Commission."

The year 1973 marked the highest peak of IAU activity up to now. Besides the Gen eral Assembly in Sydney, and the Extraordinary General Assembly in Poland, there were held eleven IAU Symposia and one Colloquium. Several IAU Publications cover this activity. The Proceedings of the Symposia are published in separate Volumes, while the Transactions of the General Assembly and of the Extraordinary General Assembly contain short reports of the Commission meetings, the administrative sessions, and the opening ceremonies. The present Volume covers some of the scientific Highlights of the General As sembly and of the Extraordinary General Assembly. It contains five Invited Dis courses given in Sydney and Poland, some selected papers, and the Joint Discussions at the General Assembly of Sydney. Of course, there were many more papers of special interest presented in Sydney that could not be included in this Volume. Their titles can be seen in the reports of the various Commissions. It is regrettable that the Invited Discourses of C. H. Townes (Interstellar Molecules) and F. J. Low (Infrared Astronomy) were not submitted for publication. Also only five papers or abstracts of the Joint Discussion on the 'Origins of the Moon and Satellites' have been available. Despite these minor shortcomings, I believe that the present Volume is faithful to its title: it gives a substantial part of the Highlights of Astronomy in 1973.

This book is the result of a meeting held in August, 1986 in Irsee, West Germany. As the title suggests, the aim of the meeting was to discuss physical processes in interstellar clouds, determine the current status, aims and future direction of the research in this area. Interstellar clouds contain nearly all the mass of diffuse gas in our galaxy, some 10% of the total galactic mass. They represent the birth site for stars and the final "dumping ground" for matter ejected from stars (winds, ex plosive ejecta) and thus play an integral part in the galactic recycling of material. Not only are the clouds important for the structure and evolution of our galaxy, they are also interesting objects of study "per se." Because of their vast scales (up to about 100 parsec), extreme temperatures (as low as about lOOK), and long life 8 times (estimated a about 10 years) a number of physical and chemical processes occur in these environments, which we are not able to study elesewhere, certainly not in laboratories. It is for this reason that the meeting, and hence this book, was organized in such a way that firstly the latest observational results were sum m ized, going from the global, large scales, to finer details and dynamics, then progressing onwards to the processes -dynamical, chemical, electromagnetic, etc."

IX LIST OF PRINCIPAL SPEAKERS XI LIST OF PARTICIPANTS 1. REGULARIZATION E. STIEFEL / A Linear Theory of the Perturbed Two-Body Problem (Regul- ization) 3 J. WALDVOGEL / Collision Singularities in Gravitational Problems 21 D. C. HEGGIE / Regularization Using a Time-Transformation Only 34 J. BAUMGAR TE / Stabilization of the Differential Equations of Keplerian Motion 38 F. NAHON / The Particular Solutions of Levi-Civita 45 O. GODAR T / Example ofIntegration of Strongly Oscillating Systems 53 w. BLACK / The Application of Recurrence Relations to Special Perturbation Methods 61 D. G. BETTIS / Numerical Solution of Ordinary Differential Equations (Abstract) 71 II. THE THREE-BODY PROBLEM V. SZEBEHELY / Recent Advances in the Problem of Three Bodies 75 R. F. ARENSTORF / Periodic Elliptic Motion in the Problem of Three Bodies (Abstract) 107 G. KATSIARIS and c. L. GOUDAS / On a Conjecture by Poincare 109 G. KATSIARIS / The Three-Dimensional Elliptic Problem 118 P. G. KAZANTZIS / Second and Third Order Variations of the Three Dimensional Restricted Problem 135 c. G. ZAGOURAS / Planar Periodic Orbits Using Second and Third Variations 146 E. RABE / Elliptic Restricted Problem: Fourth-Order Stability Analysis of the Triangular Points 156 P. GUILLAUME / A Linear Description of the Second Species Solutions 161 III. THE N-BODY PROBLEM AND STELLAR DYNAMICS G. CONTOPOULOS / Problems of Stellar Dynamics 177 w. T. KYNER / Invariant Manifolds in Celestial Mechanics 192 s. J.

The IAU Colloquium No. 59, "The effects of mass loss on Stellar Evolution" was held on September 15-19, 1980 at the International Centre for Theoretical Physics, Miramare, Trieste (Italy), under the auspices of the IAU Executive Co~ mittee and the Italian National Council of Research. The planning of this conference began two years ago du ring the IAU Symposium No. 83 "Mass loss and evolution of 0 type stars" (Qualicum Beach, Victoria, Canada) when we felt that mass loss and its effects on the evolution of stars was too broad a subject for being confined to 0 type stars only. Therefore we thought that a conference dealing with the general problem of mass loss across the whole HR diagram would have been of interest to all people working in the field. The main idea was that bringing together Astronomers and Astrophysicists of the widest range of interests and e~ pertize - all in some way related to the problem of mass loss from stars - would have spurred thorough discussions on the many aspects and implications of this topic. We hope this goal has been achieved. Furthermore, the most recent observational and theoreti cal developments on the problem of mass loss from early ty pe stars avoided this meeting to be a simple updating of the Qualicum Beach Symposium as far as this issue is concerned.

The aim of the present book will be to provide a comprehensive account of our present knowledge of the theory of dynamical phenomena exhibited by elose binary systems; and on the basis of such phenomena as have been attested by available observations to outline probable evolutionary trends of such systems in the course of time. The evolution of the stars - motivated by nuelear as weIl as gravitation al energy sources - constitutes nowadays a well-established branch of stellar astronomy. No theo ries of such an evolution are as yet sufficently specific - let alone infallible - not to require continual tests by a confrontation of their consequences with the observed prop erties of actual stars at different stages of their evolution. The discriminating power of such tests depends, of course, on the range of information offered by the test objects. Single stars which move alone in space are now known to represent only a minority of objects constituting our Galaxy (cf. Chapter 1-2); and are, moreover, not very revealing of their basic physical characteristics - such as their masses or absolute dimensions. If there were no binary systems in the sky, the only star whose vital statistics would be fully known to us would be our Sun.

Radio techniques were the nrst to lead astronomy away from the quiescent and limited Universe revealed by traditional observations at optical wave lengths. In the earliest days of radio astronomy, a handful of radio physicists and engineers made one startling discovery after another as they opened up the radio sky. With this collection of classic papers and the extensive intro ductory material, the reader can experience these exciting discoveries, as well as understand the developing techniques and follow the motivations which prompted the various lines of inquiry. For instance he or she will follow in detail the several attempts to detect radio waves from the sun at the turn of the century; the unravelling by Jansky of a "steady hiss type static"; the incredible story of Reber who built a 9 meter dish in his backyard in 1937 and then mapped the Milky Way; the vital discoveries by Hey and colleagues of radio bursts from the Sun and of a discrete source in the constellation of Cygnus; the development of receivers and interferometry in the post-war years by the groups led by Ryle in Cambridge and Pawsey in Sydney; the nrst measurements and exciting identiftcations of Taurus A (the Crab Nebula), Centaurus A, Virgo A, Cassiopeia A, and Cygnus A, the last opening the neld of radio cosmology; the early development of synchroton theory; and the prediction and discovery seven years later of the 21 cm line of neutral hy drogen."

The publication of this book is extremely timely, for the next major advances in manned space flight after Project Apollo will most likely be made in earth orbital operations. Manned exploration of the moon will certainly continue after the initial landing, but it will be performed essentially with the Saturn V launch vehicles and Apollo spacecraft developed in Apollo, especially in the early phases. Modifications to this basic hardware will increase operating capabilities to permit extensive lunar explo ration during prolonged stay times by the astronauts on the moon's surface. Manned orbital space stations have been studied for years, and NASA is already well along in development of its first attempt to provide more spacious accommo dations for astronaut-scientists in its Saturn Workshop program. While the Workshop is certainly not the ultimate space station of which our technology is capable, it is a workable, poor man's approach to the immediate need for using and expanding our present manned space flight capability without a de trimentalloss of momentum. The approach of converting a Saturn rocket stage into a manned laboratory and observatory in space is an improvisation that matches the use of the jerry-built Jupiter C back in 1958 to launch Explorer I. Let's hope that it can get the job done just as effectively."

This volume contains the proceedings of the third IAU conference on the Gravita tional N-Body Problem. The first IAU conference [IJ, six years ago, was motivated by the renaissance in Celestial Mechanics following the launching of artificial earth satellites, and was an attempt to bring to bear on the problems of Stellar Dynamics the sophisticated analytical techniques of Celestial Mechanics. That meeting was an outgrowth of the 'Summer Institutes in Celestial Mechanics' initiated by Dirk Brouwer. By the second IAU conference [2J, our interest had been captured by the attempts to simulate stellar systems on the computer. Computer simulation is now an essential part of stellar dynamics; journals of computational physics have started in the United Kingdom and in the United States and symposia on computer simulation of many-body problems have become a perennial event [3,4, 5]. Although our early hopes that the computer would 'solve' our problem have been tempered by experience, some techniques of computer simulation have now matured through five years of testing and use. A working description of the six most popular methods is appended to this volume. During the past three years, stellar dynamicists have followed closely the develop ments in the related field of Plasma Physics. The contexts of Plasma and Stellar Physics are deceptively similar; at first, results from Plasma Physics were bodily transferred to stellar systems by 'changing the sign of the coupling'. We are more sophisticated and more skeptical now.

in this work, we must therefore assume several abstract concepts that hardly need defending at this point in the history of mechanics. Most notably, these include the concept of the point particle and the concept of the inertial observer. The study of the relativistic particle system is undertaken here by means of a particular classical theory, which also exists on the quantum level, and which is especially suited to the many-body system in flat spacetime. In its fundamental postulates, the theory may be consid ered to be primarily the work of E.C.G. Stiickelberg in the 1940's, and of L.P. Horwitz and C. Piron in the 1970's, who may be said to have provided the generalization of Stiickelberg's theory to the many-body system. The references for these works may be found in Chapter 1. The theory itself may be legitimately called off-shell Hamiltonian dynamics, parameterized relativistic mechanics, or even classical event dynamics. The most important feature of the theory is probably the use of an invariant world time parameter, usually denoted T, which provides an evolution time for the system in such as way as to allow manifest co variance within a Hamiltonian formalism. In general, this parameter is neither a Lorentz-frame time, nor the proper time of the particles in the system."