The perfect companion piece to the CRISIS ON INFINITE EARTHS and HISTORY OF THE DC UNIVERSE trade paperbacks, this book features the classic tales of interaction between the heroes of Earth-One and Earth-Two. Existing in two different realities, the heroes of the Justice League team up with their predecessors the Justice Society of America in order to save both their worlds. Featuring different incarnations of Batman, Superman, the Flash and many other classic heroes.

The Justice League of America teams up yet again with their heroic predecesors, The Justice Society of America, in this new collection featuring two adventures that have never been reprinted before. First, the two teams face the threat of the Ultra Humanite and the Secret Society of Super-Villains. Then, the JLA and JSA battle alongside the All-Star Squadron against the Crime Syndicate. This volume collects JUSTICE LEAGUE OF AMERICA #195-197, 207-209 and ALL-STAR SQUADRON #14-15.

Two Earths! Parallel worlds, separated by both time and space, each unaware of the existence of the other. A generation of heroes arises on each planet. Although strikingly alike, they remain distinctly unique. The two worlds are forever linked when the scarlet speedster called the Flash pierces the dimensional veil and encounters his amazing counterpart - an older, wiser Flash. This incredible discovery changes the course of history! Contains: · Green Lantern (Volume 2) #40 · Showcase #55-#56 · The Brave and the Bold #61 · The Flash #123, #129, #137, #151 · Spectre #7