appeared in All-American Comics #19 (October 1940) and was created by writer Bill O'Connor and artist Ben Flinton. The character continued to appear on and off through issue #72 (April 1946). In 1947, the Atom moved from All-American Comics to Flash Comics with issue #80 (February 1947), and continued until issue #104 (February 1949).

In winter 1940, the Atom also began appearing in All Star Comics as a member of