From the introduction:
This guidebook is an overly-ambitious attempt to provide a complete and fully-fleshed depiction of the world of Tanaeum, in order to facilitate campaigns set in that world. Tanaeum is intended as a campaign world for use with the d20 System, and most of the mechanics adhere closely to those of third edition Dungeons & Dragons.
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The Guidebook is broken up into several sections:
Intro & Reference contains introductory material, such as the page you're reading, as well as suggestions for running adventures in Tanaeum and a handy Glossary of Terms.
The World section contains maps of the great continent Tanaeum and its six major regions. It also contains detailed descriptions of the nations and places of interest within those regions. In addition, a bestiary of creatures native to Tanaeum is included in this section.
Culture contains information about the beliefs and powers of Tanaeum's inhabitants, as well as information on the cosmology and history of the world.
Characters details the various dominant races of Tanaeum and their statistics for use in creating characters. It describes the place of standard Dungeons & Dragons character classes in Tanaeum, as well as several new Prestige Classes unique to this world. An optional segment on using standard D&D races in Tanaeum is also included in this section.
Language covers the various spoken tongues of Tanaeum, with extensive coverage of Hemmedic, the root of most Tanaean languages.
Magic lists the spells, rites and magical artifacts unique to Tanaeum.