Note: This review was originally posted on another site in 1999. Minor modifications have been made. Since I wrote the review below, a newer version of these three volumes with different authors has been published, with the original volumes reprinted as The Original Encyclopedia of Comic Book Heroes Volumes 1-3.I'm covering these three as a group as they're similarly formatted. Each book takes a different heroes and covers books in which they place a feature (not guest or part of team) role up to the mid-1960s (except for Brave and the Bold appearances), with only minor references to the 1970s when the books were originally published. Characters, key locations, etc. are covered alphabetically. Every key character in a given story in their adventures (in Fleischer's opinion) is covered. Incongruities in the text are noted and characters' psychology is examined.
Book 1 is Batman, Book 2 is Wonder Woman, and Book 3 is Superman (The Great Superman Book). Superman was originally intended for a later volume, but the series got cancelled prematurely. If I understand correctly, the Superman came out (much later) to coincide with the Superman movie.
There is some overlap of entries in the Superman and Batman volumes due to team-ups. Even so, all three volumes are a great resource for people wanting information on the heroes' early years. Don't let the fact that these books came out in the 1970s put you off from trying to find all three volumes.
2012 addendum: it’s also worth noting that these volumes don’t distinguish between Earth-1 and Earth-2 and treat the chronicles as belonging to the same character. However, some of the discrepancies between stories that are noted have been explained away elsewhere as taking place on different Earths.