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.
Olag Greck is a con man and arch criminal, and he's hiding out exactly where you might expect: among his own wretched kind on the smuggler moon Nar Shaddaa. But knowing where he is and actually arresting him are two completely different matters, as the newly deputized Artoo-Detoo and See-Threepio discover!