Unofficial LEGO Sets/Parts Collectors' Guide, free chapter!
Gary Istok (istokg in the forum) is the world's authority on the history of LEGO and its products, as anyone who's read his posts in the forum will attest. He's just finished work on the second edition of his Unofficial LEGO Sets/Parts Collectors' Guide 1949-1990s, published on DVD, and it's now available for immediate worldwide shipping from his BrickLink store for US$30.
My copy is on order so I can't fully review it yet, but I have seen some sample chapters and they are excellent. Gary has agreed to make a sample chapter available, exclusively through Brickset, so you can judge for yourself the quality of the information and images, some of which are from this site.
- Download the sample chapter, LEGO Trains 1980-91
If you have any interest in LEGO products , particularly those made during the early years of the company (which are not covered here at Brickset, yet) this is an essential purchase. Expect to see a review here when I have my copy.
 so that'll be everyone reading this, surely!