Those of you with eidetic memories will recall that Sybex had an ad for its guides at E3, which included an image of a Halo guide--and that when we asked Bungie employees there about it, they said Sybex was being (at the least) somewhat premature. :-)
Well, halo.bungie.org noticed Halo: Sybex's Official Strategies and Secrets being offered at Amazon.com. It's still obviously inaccurate in certain ways--the projected release date of the guide is January 2001 and the comparative prices and savings bit doesn't really add up--but hopefully there's more there than last time.