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.
Hidden away at birth, he would believe himself an orphan. Watched over by a mysterious hermit, he would discover incredible abilities. And by finding hope where others found only evil, he would restore balance to the galaxy.
This is the legendary story of Luke Skywalker, from his childhood on Tatooine to his fierce battle with his toughest enemy—himself.
While accompanying Princess Leia to the world of Aridus to convince the native Chubbits to join the fledgling New Republic several months after the Battle of Endor, Luke Skywalker looks back on his life up to that point.