The program allows you to maintain your own set(s) of openings next to, or in place of the main book supplied with the program. Multiple user books may exist and up to eight books can be active at the same time. Switching between user books can done at any time during the game.
Various functions related to the user book can be found below the Book maintenance sub menu located under the File menu. It is also possible to let the selected Chess engine handle it’s own book, in that case some of the functions described below are not active.

Some additional options are available from the book moves window by selecting the books tab.
The next topics describe each book function.