Journey into Mystery is an American comic book series initially published by Atlas Comics, then by its successor, Marvel Comics. Initially a horror comics anthology, it changed to giant-monster and science fiction stories in the late 1950s. Beginning with issue #83, it ran the superhero feature "The Mighty Thor", created by writers Stan Lee and Larry Lieber and artist Jack Kirby, and inspired by the mythological Norse thunder god. The series, which was renamed for its superhero star with issue #126, has been revived three times: in the 1970s as a horror anthology, and in the 1990s and 2010s with characters from Marvel's Thor mythos. The title was also used in 2019 for a limited series as part of the "War of the Realms" storyline.

Atlas Comics was the 1950s comic-book publishing label that evolved into Marvel Comics. Magazine and paperback novel publisher Martin Goodman, whose business strategy involved having a multitude of corporate entities, used Atlas as the umbrella name for his comic-book division during this time. Atlas evolved out of Goodman's 1940s comic-book division, Timely Comics, and was located on the 14th floor of the Empire State Building. This company is distinct from the 1970s comic-book company, also founded by Goodman, that is known as Atlas/Seaboard Comics.