Tom Brevoort, Marvel's senior vice president of publishing, has begun digging into his archives for The Marvel Age of Comics, his new Tumblr blog devoted to "rarities and original art from the formative days of Marvel." It launched just yesterday, and there's already some terrific images, including a page of original art from 1941's Captain America Comics #6, John Byrne's character sheet for Kitty Pryde and, above, Jim Steranko's Christmas card from when he was working on Nick Fury, Agent of S.H.I.E.L.D.