Journey into Mystery featured monster and science fiction stories and is memorable also for featuring the debut of a prototype of the Hulk in issue #62. With the start of the Silver Age of Comics, Marvel switched the feature to superhero stories and introduced Thor and in issue #83, inspired by the Norse thunder god and by writer Stan Lee's musings that comic books were the mythology of the modern day. Journey into Mystery primarily featured Thor stories through issue #125 and Journey into Mystery Annual #1, at which point the series was retitled The Mighty Thor.
As a consequence of Heroes Reborn, Thor dropped out of his own series beginning with issue #503 and his book's title was restored to Journey into Mystery. The series continued with the "Lost Gods" storyline (which ran through issue #513) and then with a rotating cast of characters, until finally ending with Journey into Mystery #521 in 1996.