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.
A New Hope presents Vader as a formidable villain who's not afraid to get his hands dirty—infiltrating Rebel ships in the thick of the action, getting behind the yoke of a ship to shoot down the good guys, going to-to-toe with Obi-Wan Kenobi. But, well, there's one scene that just doesn't quite fit. Remember when Vader's first on-screen Force choke? He wins the argument in the Death Star's boardroom against a mouthy Admiral Tagge. But then he's talked down by Grand Moff Tarkin! What is Vader doing taking orders from a bureaucrat? Age of Rebellion: Darth Vader explores Vader's place in the Empire's hierarchy.
DARTH VADER may be the most feared man in the galaxy. But to the proud Grand Moffs of THE EMPIRE, he's just the Emperor's apprentice – below them in the hierarchy. But what fury burns in the heart of a SITH with such overwhelming rage when a mere Moff dares command him? And at what point does Darth Vader show them his true power?