The BX Advanced Bestiary Volume 3 (Monsters L-R) takes the monsters in the OSE Basic book alphabetically and expands on them offering variants special abilities that can be added and flavor and background to make them more interesting.

The book is an 8 1/2 x 11 hardcover with sewn binding ribbon bookmark and black and white interior. The book covers monsters from the OSE Classic Rules tome from Leech giant to Rust Monster and adds new variants creatures based on the theme and options. Includes four new classes.