Official Crisis on Infinite Earths Index #1 (1986)

Contains a history of the Multiverse concept, a near-complete list of alternate Earths, and extremely detailed info on each issue of the series. (Cover description, credits, feature characters, guest stars, villains, guest appearances, other characters, synopsis, etc.) Incredibly detailed; includes things like "Guest Star: Guardians of the Universe (appearance here same as Green Lantern (second series) #194, page 15; appear next, imprisoned, in Green Lantern (second series) #195, page 19, to be freed in issue #5, page 13." Positively intimidating to a casual annotater like myself.The cover deserves a mention. It's by Pérez, and is merely gorgeous at first glance... until you realize what all those characters have in common. Notable emotional impact.
Release Date: 1986