The third edition of this book has been completely revised. It is intended for first- and second-year undergraduates in chemistry, and for undergraduates in other science and engineering subjects which require an understanding of chemistry.The author gives more attention to the solid and liquid states than is found in most other books on physical chemistry, and introduces topics such as computer simulation and quasicrystals, Each chapter concludes with a set of problems designed to lead the reader to familiarity with the subject and its application in new situations. Computer programs designed to assist the reader are downloadable from the Worldwide Web (www. cup. cam.ac.uk). Detailed solutions to the problems are available on the same internet, while brief answers are contained within the book itself. Stereoviews are presented for three-dimensional structures and instructions for viewing them are provided. The book assumes only pre-degree mathematics, and special mathematical and other topics are contained in appendices.This modern text on physical chemistry will be of interest to undergraduate students in chemistry and also to students in other areas of science and engineering requiring a familiarity with the subject.