1Traditional dictionaries of philosophy provide a great deal of detailed information and define a large number of uncommon terms. By contrast, The Ism Book is more of a "field guide" that cuts to the essence of key concepts in the history of ideas. The longest-running dictionary of philosophy on the Internet (continually maintained since 1996), The Ism Book is finally available in paperback and ebook formats for convenient reference. Naturally, the online version is still available at ismbook.com.