The project had its genesis in late 1993, when Pocket Books editor Kevin Ryan approached Erdmann and asked him if he would be interested in writing the Companion. Erdmann agreed, and, over the next six years, conducted interviews with a wide range of people involved in the series.
The Companion takes a look at the creative processes behind each season and then has a detailed episode guide. Following each episode entry is the behind the scenes information. The book is 736 pages long, and features numerous black and white pictures.
An unrelated CD-ROM also called the Star Trek: Deep Space Nine Companion (ISBN 978-0-671-31785-0) was released in 1999, and features the scripts for the entire series and the trailers for each episode featuring Don LaFontaine as the announcer, among others.