This book is concerned with the prediction of thermodynamic and transport properties of gases and liquids. The prediction of such properties is essential for the solution of many problems encountered in chemical and process engineering as well as in other areas of science and technology. The book aims to present the best of those modern methods which are capable of practical application. It begins with basic scientific principles and formal results which are subsequently developed into practical methods of prediction. Numerous examples, supported by a suite of computer programmes, illustrate applications of the methods. The book is aimed primarily at the student market (for both undergraduate and taught postgraduate courses) but it will also be useful for those engaged in research and for chemical and process engineering professionals.