There have been several characters in the world of DC Comics named "The Flash".
The first Flash was a man named Jay Garrick. Jay Garrick was created by writer Gardner Fox. The character first appeared in the first issue of the Flash Comics in January 1940. His adventures were published during a time comic book fans call The Golden Age.
The character was teamed up with other heroes during World War II and formed The Justice Society of America. He appeared regularly in comics until 1951.
In 1956, DC Comics decide to recreate the Flash. They gave him a new costume and name. This Flash was named Barry Allen. He was completely unrelated to Jay Garrick. In fact, as far as the new Flash was concerned, Jay Garrick never existed. Barry Allen's first appearance shows him reading an old comic book where Jay Garrick was "just a character some writer dreamed up".
This Flash's adventures where published during what comic book fans refer to as The Silver Age. The Flash had a sidekick named Wally West who became known as Kid Flash.
Eventually, it was decided that the superheroes who had adventures in The Golden Age actually existed in a parallel universe. This allowed all sorts of different heroes team up.
In 1985, DC Comics merged all of its fictional characters into a single shared universe. One of the greatest comic book series ever, Crisis On Infinite Earths, presented all of its heroes fighting to save the universe. In a last ditch effort to save everyone, Barry Allen sacrificed his life.
His sidekick, Kid Flash, took upon the name of The Flash. He was the Flash during a time comic fans call The Modern Age.
There is kind of a sad note to all of this. I mentioned at the top of this post that the character of Jay Garrick last appeared in 1951. He was "revived" and the concept of parallel Earths introduced in September 1961, in Flash #123. The story was called "Flash of Two Worlds."
The story was co-created and drawn by a man named Carmine Infantino. Mr. Infantino was a major force during The Silver Age of comics. Mr. Infantino died last week. He was 87 years old. When he died, the publisher of DC Comics, a man named Dan DiDio wrote the following:
"There are few people in this world that have had as much of an impact on the industry as Carmine. He bridged both the Golden and Silver Ages of comics, shepherding in some of the most successful periods in our history and setting the course of our characters that is still seen today. He will be greatly missed, but his legacy will remain forever."