The Flash #123; Flash of Two Worlds! The second most important DC story from the Silver Age. A story that could only be eclipsed by another Flash story — Mystery of the Human Thunderbolt from Showcase #4 — the story that gave birth to the Silver Age itself. No other story influenced the landscape of the DC line of comics over the next two decades more than The Flash #123. As if an appearance by the Golden Age Flash weren't important enough, it was the parallel-world explanation as to how he could team with his Silver Age namesake that made this story so important — the establishment of Earth-One/Earth-Two. Not to say that the remainder of this issue is simply filler! Drawing upon one of the greatest rogues galleries in all of comics, the issues collected herein feature some of Flash's most fearsome foes, showcasing the first appearance of Captain Boomerang, and the return of the Mirror Master and The Trickster, but also returning are Flash's greatest allies and co-stars: Kid Flash and the Elongated Man! With an A-list lead character and a stellar supporting cast, The Flash was never a boring read. The creativity of the stories and the magnificent artwork of Carmine Infantino, Joe Giella and Murphy Anderson is as exciting today as it was then, making The Flash one of the most memorable series in the history of the medium.