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.
The Death Star has been destroyed. But back at the Rebel base, the celebration is over. The Alliance has intercepted a coded transmission, indicating that the Empire is determined to discover which pilot was responsible for the destruction of the Death Star. New security protocol is in effect: The details of the Death Star mission are now top secret, and no one is to know that Luke fired the decisive shot.
But that's hardly the Alliance's only problem. Almost all their finances were lost with the destruction of Alderaan – and they are out of money. Their last hope is to access the secret accounts on Muunilinst, the former home of the InterGalactic Banking Clan, and the financial heart of the galaxy. So Luke, Leia, Han, Chewbacca, and the droids head for Muunilinst.
The Empire's top assassin will be waiting for them.