This is the third edition of the successful text-reference book that covers computational chemistry. It features changes to the presentation of key concepts and includes revised and new material with several expanded exercises at various levels such as 'harder questions' for those ready to be tested in greater depth - this aspect is absent from other textbooks in the field. Although introductory and assuming no prior knowledge of computational chemistry, it covers the essential aspects of the subject. There are several introductory textbooks on computational chemistry; this one is (as in its previous editions) a unique textbook in the field with copious exercises (and questions) and solutions with discussions. Noteworthy is the fact that it is the only book at the introductory level that shows in detail yet clearly how matrices are used in one important aspect of computational chemistry. It also serves as an essential guide for researchers, and as a reference book.

Prof. Dr. E.G. Lewars Errol G. Lewars obtained his Ph.D. with Peter Yates at the University of Toronto, synthesizing "unnatural products", then worked with R. B. Woodward at Harvard on vitamin B12, and with J. F. King at the University of Western Ontario on organosulfur compounds.He is currently Professor of Chemistry at Trent University, Peterborough, Ontario, Canada. The development of methods which provided a realistic assessment of the properties of unknown compounds induced him to move into computational chemistry.His work "Computational Chemistry. An Introduction to the Theory and Applications of Molecular and Quantum Mechanics" (published by Kluwer, 2003) was named as CHOICE magazine's "Outstanding Academic Title" of 2004.