"Unusual Tales", a series presenting Steve Ditko's comics from 1957 to 1959 that are in the public domain.
But before the story, some links:
Classic MOCKER graphic novel available
Back issues and subscriptions available
Ditko's Legion of Super-Heroes stories in DC's DITKO OMNIBUS v2
Scans in this series generally adapted to my personal tastes from those copies
Click to embiggen