Action Comics from April 1938 featured the very first appearance of Superman. Today it is considered the most valuable comic book of all time, and one of the very few known copies just went up for auction.
This was a comic fully dedicated to Superman, but it was a reprint of the original “Action Comics Story,” which was published in the summer of 1930. Description from cecilbuffington.com. I searched for this on bing.com/images