Stan Lee is one of the true comics legends. Few comics writers have created so many popular and enduring franchises. His 1960s superhero creations for Marvel Comics were instrumental in the so-called "Silver Age of Comic Books", a period of artistic advancement and commercial success in mainstream comic books.
He co-created 'The Fantastic Four' (1961, with Jack Kirby), 'Spider-Man' (1962, with Steve Ditko), 'Thor' (1962, with Jack Kirby and Larry Lieber), 'The Incredible Hulk' (1962, with Kirby), 'The X-Men' (1963, with Kirby), 'Iron Man' (1963, with Lieber, Kirby and Don Heck), 'The Avengers' (1963, with Kirby), 'Sgt Fury and His Howling Commandos' (1963 with Kirby and Dick Ayers), 'Doctor Strange' (1963, with Ditko), 'Daredevil' (1964, with Kirby and Bill Everett), 'Hawkeye' (1964, with Heck) and 'The Silver Surfer' (1966, with Kirby and John Buscema).
He pioneered the idea of having all these characters frequently cross-over with one another. This 'shared' universe made their respective mythologies stronger and promoted them to readers unfamiliar with them.