The authors' aim is to present a review of experimental and theoretical research that has been done to establish and to explain the physical properties of actinide compounds. The book is aimed at physicists and chemists. It was thought useful to collect a large selection of diagrams of experimental data scattered in the literature. Experiment and theory are presented separately, with cross references. Not all work has been included: rather, typical examples are discussed. We apologize to all researchers whose work has not been quoted. Since we report on an active field of research, clearly the data and their interpretation are subject to change. We benefitted greatly from discussions with many of our colleagues, particularly with Drs. G. H. Lander and W. Suski. The help of Mrs. C. Bovey and Ch. Lewis in the preparation of the manuscript, and the artwork and photo graphic work of Ms. Y. Magnenat and E. Spielmann of the Institute of Experi mental Physics of the University of Lausanne, are gratefully acknowledged. Our particular thanks are due to Ms. J. Ubby for her skillful and patient editorial work."

This book discusses various problems in elementary number theory, most of which have a combinatorial flavor. In general classical problems are avoided and almost no proofs are given for the presented problems. Both the difficulty and importance of the problems discussed are very variable in some are only exercises while others are very difficult or even hopeless and may have important consequences or their eventual solution may lead to important advances and the discovery of new methods. This new edition is the joint work of the late Paul Erdys, Ron Graham, and as new co-authors, Melvin Nathanson and Xingde Jia.