From 1987: possibly one of the most important single books of the Star Age: the STAR WARS SOURCEBOOK, a spin-off from the West End RPG published to mark the tenth anniversary of the release of the original movie.
This hardback (the game itself was a similar format) really helped to kickstart the saga's return after several years of languishing in the doldrums. By opening up the Expanded Universe, and targeting buyers that had grown up with, but then abandoned, the series, West End and Lucasfilm reminded fandom just how good the movies had been. And how much potential there was for storytelling within the Star Wars universe.
The writers started to flesh out what we'd seen on screen by filling in many of the gaps. Later on, the writers of the numerous novels, comics and games would take this so far that every minor character and moment from the films was fleshed out to ridiculous levels. But, at this point, it was something new and different.
Flushed with early success, the publisher went on to release books specifically about the forces of the Empire and Rebellion and then expanded the range to complement the various books and comics series.
The books featured reams of statistics that were gobbledygook to anyone who didn't play the games (like me) but the extensive text, blueprints, floor plans and (in some volumes) original art still made these must-haves for the lapsed Star Warrior like myself.
The one other single publication that renewed my interest in the dormant franchise was Starlog's tenth anniversary salute.
West End deserve full recognition for their part in saving Star Wars, even through the continuity they helped to create was swept away when Disney hit the reset button in the run up to the release of the new movie.