Earth-One? Earth-Two? Infinite Earths? Where did it all begin? Collecting the classic team-ups of the JLA (Justice League of America) and the JSA (Justice Society of America), these are the timeless adventures that changed the DC universe forever, and set the scene for the universe-shattering Crisis on Infinite Earths! The JLA and JSA must team up to fight a host of villains, from Dr. Alchemy to Felix Faust; the Crime Syndicate of Earth Three (as seen in JLA: Earth 2); an evil version of genie-commanding hero Johnny Thunder; and the Anti-Matter Man, who threatens to destroy both Earths One and Two!