Brave and the Bold is one of DC’s most celebrated comic books, so much so that not only has it been revived, but a TV series was created to pay tribute to it. The idea behind it was that each issue would feature a teamup. In #58, Kid Flash, Aqualad, and Robin investigated a disappearance of several teenagers from a town. Although they weren’t explicitly called the Teen Titans, this is generally considered the first appearance of the team. I believe writer Bob Haney wanted to create the team as an attempt to reach the readers of Amazing Spider-Man, by giving them a team of teenagers to identify with. (Granted, Haney isn’t the best at writing dialogue for teenagers, but everyone has weaknesses) This was basically an experiment.
However, in the next issue, the Teen Titans were officially formed. Robin formed the team because he felt left out of Justice League missions because he was too young. So he got both Kid Flash and Aqualad to join him. Also joining the team is a kind of new heroine named Wonder Girl. Haney had made a mistake. Wonder Girl had originally been created to make Wonder Woman more wholesome. She was given two sidekicks, Wonder Girl and Wonder Tot, both of whom were actually younger versions of Wonder Woman. Haney didn’t realize that Wonder Girl was supposedly not supposed to even exist on this timeline. So he created Donna Troy, unwillingly starting a continuity snarl that to this day subsequent writers just can’t resist trying to “fix”, and each time, they make it worse and worse.
The Titans eventually got their own comic, which lasted 43 issues. In addition to the initial quartet, two possible fifth members were tried out during the Silver Age. First came Beast Boy of the Doom Patrol, but the Patrol wouldn’t allow him to permanently join. The more successful addition was Green Arrow’s ward Roy Harper, Speedy. As the comic continued, other members joined: Lilith Clay, Malcolm Duncan and the duo Hawk and Dove (more on Hawk and Dove soon!) But soon came the 80’s, and a successful revival by Marv Wolfman and George Pérez. But that is for the Bronze Age.
Next: Flying Blind