Stan Lee, the man almost synonymous with Marvel Comics, turns 90 Friday. Born in 1922, Lee refuses to slow down, making cameo appearances in films and staying active on Twitter.

Stan Lee was born Stanley Leiber. Before Lee defined comic books at Marvel Comics, he worked in nearly every aspect of the comics-publishing industry. Lee began as an assistant for Timely Comics, and his first writing credit was for text filler in “Captain America Comics." He became Timely's interim editor the same year, 1941.

It took nearly 20 years before Lee changed the comics landscape forever. After DC Comics created the Justice League of America -- featuring Superman, Aquaman, Batman, Flash, Green Lantern, Martian Manhunter, and Wonder Woman -- Lee was tasked to create his own superhero team to compete with its success.

Lee collaborated with Jack Kirby to create the Fantastic Four. Timely became Atlas Comics in 1951, and it was Marvel Comics by 1961. The collaboration between Lee and Kirby during the 1960s created a slew of superheroes that would dominate the comic-book industry and, later, the film industry.

Lee, spearheading Marvel, co-created Spider-Man, Hulk, Iron Man, Thor, and the X-Men, among others, with Kirby illustrating many of the comics. 

With “The Avengers” dominating movie-theater box offices this year, the successful reboot of “The Amazing Spider-Man,” and the forthcoming Wolverine and X-Men productions, Lee's legacy will continue for the next generation of comic fans. Lee -- with his trademark signoff, “Excelsior!” and humor -- made cameo appearances in “The Avengers” and “The Amazing Spider-Man,” and he took to Twitter to thank fans for all the birthday wishes.

And Lee did not pass up an opportunity to comment on the recent death of one of his greatest creations, Peter Parker. Lee sent a tweet to Dan Slott, the writer responsible for the death of Peter Parker in “The Amazing Spider-Man #700,” saying, “What a gift, some guys give a nice cigar, a watch, but no not you, I get a dead #PeterParker Thanks for the bday wishes my friend!”