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.
Deadly assassin X-7 has never failed to complete a mission--until now. Unmasked and unarmed, he narrowly escapes from the Rebels with his life and little else. His cover may be blown, but he's not returning to Commander Rezi Soresh until his target has been eliminated. This time, he has a new plan. He'll gather six of the best pilots in the galaxy–all of them roguish mercenaries who care only about money–and turn them loose on Red Squadron.