The on-sale date is from the publication date recorded in the Catalog of Copyright Entries, Third Series, Vol. 1, Part 2, Nos. 1&2, Periodicals, 1946-1947.
HW notes better than usual inks on Hopper and wonders if Marcia Snyder might be involved.
Scripter added by Craig Delich. The Who's Who states that Mitchell (under the Derek West by-line) authored this strip from circa 1946-circa 1951.
Derek West is also a character in the story.