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.
Jedi vs. Sith was a series of comics published by Dark Horse Comics from April 18, 2001 to September 19, 2001, then compiled as a trade paperback on May 1, 2002.
It tells the story of the end of the New Sith Wars, the Battle of Ruusan, and how the Rule of Two came into fruition. The comic also serves to explain the origins of the Valley of the Jedi seen in The Dark Forces Saga, Star Wars: Jedi Knight: Dark Forces II, and Dark Forces: Jedi Knight