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.
This is the third trade paperback in the Star Wars: Empire series of comics. This collection of comics chronicles some parts of the war from the Imperial side, digging into what Imperial soldiers are told about the Empire. The series protagonizes the Empire, but also antagonizes Imperial High command to an extent, offering an interesting and rare look at the Empire.