Two issues, one good story. The front half of #64 is a solid Iron Man story in which Black Widow reappears and we see the costume she’ll be sticking with for a while.
The back-half of #63 is a Cap story with his origin being told, with magnificent Jack Kirby art. It’s fairly true to what everyone knows—the only major difference between it and the movie is that he serves in the military undercover as Steve Rogers, where he acts all bumbling, and also where he meets Bucky for the first time.
This is also the first time I’ve seen a mention of The MMMS, “The Merry Marvel Marching Society.” You could have joined for a buck.
Creators: Stan Lee and Don Heck (Iron Man), Stan and Jack Kirby (Captain America)
Firsts: Black Widow in costume.