This book is remarkably useful as an aid to the study of philosophy. Its huge range of entries include short biographies of important philosophers, definitions of terms, full descriptions of key arguments including problems with them, and very useful cross-references. The articles, though short, manage to be impressively detailed and informative in the short spaces afforded each of them. Some of them, though, are a little too technical, without giving a good enough general explanation - the entry on QUANTUM THEORY is a prime example, and many of the entries on subjects to do with logic or the forms of arguments are also offenders. In addition, while the original works of philosophers are mentioned, rarely if ever are suggestions made for further reading - something that would have been very welcome. For slightly more easy to understand, longer entries, including more general essays and excellent references to further reading, I recommend The Oxford Companion to Philosophy, edited by Ted Honderich. Impressively, though, A Dictionary of Philosophy does not only include philosophical entries, but also mentions several areas of mathematics and the sciences. In summary, then, it is an excellent reference text, and at the price one that every student of philosophy should own, but one which is not sufficient on its own to learn the subject from.