This week on The CW, “The Flash” wrapped up a stellar first season, ending a string of bright, colorful, and unabashedly fun episodes with an emotional finale and a hell of a cliffhanger. Like it’s titular hero, “The Flash” bolted out of the gate at top speed, with remarkably few stumbles in its freshman year. It also gave viewers a taste of something longtime DC Comics readers have known for years: That while he isn’t a part of the famed trinity of Batman, Superman, and Wonder Woman, The Flash is secretly the most important character in the entire DC Universe.

It isn’t even really a matter of opinion — sure, personal taste will dictate how much you enjoy any given Flash story, but the character’s importance is about as objective as you can get in comic books. It was The Flash that comics creators used to introduce or popularize a number of ideas that are now integral to the DC Universe, and comics as a whole. It's quite possible to chart the history of DC Comics, and to a lesser extent, mainstream superhero comics, using the Flash as a measuring stick.

The Flash made his debut in January 1940, the third of DC’s most-recognizable characters to be created in the Golden Age of comics, coming after Batman but just before Green Lantern. He was also an entirely different character than the one you might know from the current main “Flash” comic being published by DC, on the CW TV series, or the upcoming movie set to star Ezra Miller. Those are all about another Flash — Barry Allen. We’ll get to him in a moment.

The first Flash, however, was a guy named Jay Garrick.

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While his origin was different and his costume goofier than his more recognizable successor, the important part is pretty much the same: He’s a superhero who runs really fast. You don’t really have to read his stories unless you’re a die-hard Flash fan and a completist — most Golden Age comics aren’t all that great — but there are two things that are important about him. The first is a fun bit of trivia — he becomes a part of the first superhero team ever, the Justice Society of America. The second, however, is much more interesting.

The first reboot in comics

In 1956, DC Comics did something crazy: They introduced an entirely new Flash in their variety book “Showcase,” issue #4. Created by writers Robert Kanigher and John Broome with legendary artist Carmine Infantino, this new Flash was Barry Allen, a police scientist who gained his powers after getting doused by chemicals that were struck by lightning. This is where the Flash most people are familiar with began, iconic red suit and all.

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No one had ever done this before — it was, essentially, the first real reboot in superhero comics. The Flash’s success was a key part of reviving the then floundering superhero genre, which had been under attack following the publication of Fredric Wertham’s anticomic-book manifesto “The Seduction of the Innocent.” Thanks to The Flash, superheroes began to come back in a big way — and the birth of Barry Allen effectively marked the start of the Silver Age of comics.

Make sense? Good. Here’s where things get crazy.

Flash meets Flash

When Barry Allen took over as the Flash, he was originally intended to replace Jay Garrick entirely. After his first appearance in “Showcase” was deemed a success and he was placed in his own book, “The Flash,” the new series picked up where the Jay Garrick-starring “Flash Comics” left off — with issue #105.

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