Most organic molecules retain their integrity when dissolved, and even though in such cases the effects exerted by solvents are, in the language of the coordination chemist, of the "outer sphere" kind, the choice of solvent can be critical to the successful outcome of an operation or preparation. Solubilities of reactants and products must be taken into account, and even if the organic principals in the reactions retain their integrity, many of the reagents are electrolytes, and their state of aggregation will affect their reactivity. In testifying to the importance of understanding solute-solvent interactions I draw attention to a large class of inorganic species for which the involvement in the chemical and physical properties by the solvent is even more deeply seated. It is comprised by the large body of metal atoms in low oxidation states for which solvent molecules intervene as reagents. At the same time, because the ions carry charges, the effects arising from outer sphere interactions are usually greater than they are for neutral molecules. To cite an example: when FeCb(s) is dissolved in water to form a dilute - say O. OlO- solution there is a complete reorganization of the coordination sphere of the cation. Whereas in the solid each cation is surrounded by six chloride ions, in the solution the dominant form is [Fe(H20)6]3+ followed by [Fe(H20)sCI]2+, [Fe(H20)4CI2]+, etc. in rapidly decreasing abundance.

The Advanced Study Institute (AS I) entitled "Phase Transitions in Surface Films" was held at the Ettore Majorana Centre for Scientific Culture in Erice, Sicily from June 19 to June 29, 1990. It reviewed the present understanding (experimental and theoretical) of phase transitions of surfaces, interfaces, and thin ftlms as well as the related structural and dynamical properties of these systems. From its inception, this ASI was envisioned as a sequel to one of the same title organized eleven years earlier by J. G. Dash and J. Ruvalds which was also held at the Ettore Majorana Centre. The previous ASI reflected the progress which had been made in understanding quasi two-dimensional (2D) states of matter, particularly adsorbed monolayers, and the phase transitions which occur in them. At that time, the field was barely ten years old. The modern field to which we are referring here can be traced to the landmark experiments of A. Thorny and X. Duval. Beginning in 1967, they published a series of papers presenting evidence from vapor pressure measurements of 2D phases of krypton and other gases adsorbed on polycrystalline (exfoliated) graphite. Their work led to a large number of thermodynamic and scattering experiments on physisorbed ftlms. This in turn motivated a great deal of theoretical interest in 2D systems and their phase transitions.

Andreas Floer died on May 15, 1991 an untimely and tragic death. His visions and far-reaching contributions have significantly influenced the developments of mathematics. His main interests centered on the fields of dynamical systems, symplectic geometry, Yang-Mills theory and low dimensional topology. Motivated by the global existence problem of periodic solutions for Hamiltonian systems and starting from ideas of Conley, Gromov and Witten, he developed his Floer homology, providing new, powerful methods which can be applied to problems inaccessible only a few years ago. This volume opens with a short biography and three hitherto unpublished papers of Andreas Floer. It then presents a collection of invited contributions, and survey articles as well as research papers on his fields of interest, bearing testimony of the high esteem and appreciation this brilliant mathematician enjoyed among his colleagues. Authors include: A. Floer, V.I. Arnold, M. Atiyah, M. Audin, D.M. Austin, S.M. Bates, P.J. Braam, M. Chaperon, R.L. Cohen, G. Dell' Antonio, S.K. Donaldson, B. D'Onofrio, I. Ekeland, Y. Eliashberg, K.D. Ernst, R. Finthushel, A.B. Givental, H. Hofer, J.D.S. Jones, I. McAllister, D. McDuff, Y.-G. Oh, L. Polterovich, D.A. Salamon, G.B. Segal, R. Stern, C.H. Taubes, C. Viterbo, A. Weinstein, E. Witten, E. Zehnder

Andreas Floer died on May 15, 1991 an untimely and tragic death. His visions and far-reaching contributions have significantly influenced the developments of mathematics. His main interests centered on the fields of dynamical systems, symplectic geometry, Yang-Mills theory and low dimensional topology. Motivated by the global existence problem of periodic solutions for Hamiltonian systems and starting from ideas of Conley, Gromov and Witten, he developed his Floer homology, providing new, powerful methods which can be applied to problems inaccessible only a few years ago. This volume opens with a short biography and three hitherto unpublished papers of Andreas Floer. It then presents a collection of invited contributions, and survey articles as well as research papers on his fields of interest, bearing testimony of the high esteem and appreciation this brilliant mathematician enjoyed among his colleagues. Authors include: A. Floer, V.I. Arnold, M. Atiyah, M. Audin, D.M. Austin, S.M. Bates, P.J. Braam, M. Chaperon, R.L. Cohen, G. Dell' Antonio, S.K. Donaldson, B. D'Onofrio, I. Ekeland, Y. Eliashberg, K.D. Ernst, R. Finthushel, A.B. Givental, H. Hofer, J.D.S. Jones, I. McAllister, D. McDuff, Y.-G. Oh, L. Polterovich, D.A. Salamon, G.B. Segal, R. Stern, C.H. Taubes, C. Viterbo, A. Weinstein, E. Witten, E. Zehnder

Copernicus and Galileo's sun-centered model of the solar system gave us our view of space. Newton and Einstein's mechanical and electromagnetic models of the universe gave us our view of nature. Can the human condition be captured with a similarly universal model? Author Lawrence H. Taub believes so, and he develops three of them-age, sex, and caste-to reveal the deeper currents of history. The models presented in "The Spiritual Imperative" clarify the past, explain the present, and help anticipate the future. Taub uses these models to make insightful forecasts of future discontinuities that answer the major questions facing us today. Some of his predictions include: a regional political-economic block formed in the Far East and what this will mean to the world an alliance between the U.S. and Russia and how this will develop Israeli-Palestinian peace leading to a Pan-Semitic Union that will make the Middle East one of two main world centers of economic, political, and spiritual power in the mid-twenty-first century the replacement of technology with religion and spirituality as the main growth market in the twenty-first century "The Spiritual Imperative" provides insight into where human civilization has been and where it's going.

Copernicus and Galileo's sun-centered model of the solar system gave us our view of space. Newton and Einstein's mechanical and electromagnetic models of the universe gave us our view of nature. Can the human condition be captured with a similarly universal model? Author Lawrence H. Taub believes so, and he develops three of them-age, sex, and caste-to reveal the deeper currents of history. The models presented in "The Spiritual Imperative" clarify the past, explain the present, and help anticipate the future. Taub uses these models to make insightful forecasts of future discontinuities that answer the major questions facing us today. Some of his predictions include: a regional political-economic block formed in the Far East and what this will mean to the world an alliance between the U.S. and Russia and how this will develop Israeli-Palestinian peace leading to a Pan-Semitic Union that will make the Middle East one of two main world centers of economic, political, and spiritual power in the mid-twenty-first century the replacement of technology with religion and spirituality as the main growth market in the twenty-first century "The Spiritual Imperative" provides insight into where human civilization has been and where it's going.