there r varying degrees of legitimacy with the books and comics.
the olderstuff is more likely to be snuffed out by lucas himself. ie-tales...jaster mereel(boba origins).
which i find ludicris, why would lucas limited ok a story to be written then change it...answer-
the same reason he has released the movies about five or six times on different formats...dollars.
the stuff that i know is canon that is not movies- "shadows of the empire" thats really it.
even clone wars cartoon is not.
many of the books and comics carry the same weight as something you or i might write.
continuity be damned.
"mmmm, pistol whip." -Homer Simpson