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.
The Youtini Expanded Universe Ranking system is a 1-5 scale that ranks EU book quality, difficulty, and importance. Books closer to Level 1 are easier to read and understand, more important, and of higher quality.
Luke Skywalker leads a squad of fighters to destroy an Imperial Star Destroyer sent to attack a recently discovered Rebel supply base. The fighters fly through a flock of mynocks, and one attaches itself to Luke's X-wing. He shakes the mynock loose after nearly crashing and continues on with the other fighters. They destroy the Star Destroyer and head back to their base.