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 Rebel Alliance: Ships of the Fleet is an 8-page pop-up book about the ships and fighters of the Alliance to Restore the Republic. The page count is deceptive, as it has no less than five fold-outs. In addition to pop-up images, it contains pictures, drawn images, diagrams, technical specifications, and text.