star wars has different levels of canon. its not like comics. there are different levels, from the movies downwards...By 1996, Licensing was keeping an in-house bible of reference materials as the volume of publications, facts, and figures grew to such unwieldy proportions that it became difficult to know everything relevant to a particular project. They finally decided something had to be done to organize the increasingly large collection of media which chronicled the Star Wars universe. A system of canon was developed that organized the materials into what was and wasn't fit for the Star Wars story.
In 2000, Lucas Licensing appointed Leland Chee to create a continuity tracking database referred to as the "Holocron". As with every other aspect having to do with the overall story of Star Wars, the Holocron follows the canon policy that has been in effect for years.
The Holocron is divided into 5 levels: G-canon, T-canon, C-canon, S-canon, and N-canon.
G-canon is absolute canon; the movies (their most recent release), the scripts, the novelizations of the movies, the radio plays, and any statements by George Lucas himself. G-canon overrides the lower levels of canon when there is a contradiction. Within G-canon, many fans follow an unofficial progression of canonicity where the movies are the highest canon, followed by the scripts, the novelizations, and then the radio plays.
T-canon refers to the canon level comprising only the two television shows: Star Wars: The Clone Wars and the Star Wars live-action TV series. Its precedence over C-Level canon was confirmed by Chee.
C-canon is primarily composed of elements from the Expanded Universe including books, comics, and games bearing the label of Star Wars. Games and RPG sourcebooks are a special case; the stories and general background information are themselves fully C-canon, but the other elements such as character/item statistics and gameplay are, with few exceptions, N-canon.
S-canon is secondary canon; the story itself is considered non-continuity, but the non-contradicting elements are still a canon part of the Star Wars universe. This includes things like the online roleplaying game Star Wars: Galaxies and certain elements of a few N-canon stories.
N-canon is non-canon. "What-if" stories (such as stories published under the Star Wars: Infinities label), game statistics, and anything else directly contradicted by higher canon ends up here. N-canon is the only level that is not considered official canon by Lucasfilm. A significant amount of material that was previously C-canon was rendered N-canon by the release of Episodes I-III.