BBY/ABY is used to position items along the Star Wars Timeline. BBY refers to Before the Battle of Yavin. ABY refers to After the Battle of Yavin. The Battle of Yavin in Episode IV: A New Hope occured in 0 BBY/ABY.
Young Jedi Knights: The Rise of the Shadow Academy is a compilation published by the Science Fiction Book Club of the first six books in the Star Wars: Young Jedi Knights series