Third Metal Men appearance.
This story ends with a note to the readers that "This is the last trial issue of Metal Men," with a plea from the Metal Men themselves for the readers to respond. However, it wasn't quite true, as the very next issue of Showcase (#40) was another Metal Men issue.
Story in 3 parts (splash page incorrectly lists this as a "four-part thriller"): unnumbered part I (6 pp.), Part II (6 pp.), Part III (14 pp., not labeled as Part III except at end of Part II).
For the reprint in issue #42 this story was edited down, leaving out page 7, the last 1/3 of page 12, the first 1/3 and last 1/3 of page 13, and page 18; and editing the final page to remove references to the readers responding if they wanted more Metal Men.
Letters on the first tryout issue (#37) from Edward Fishman, Jerry Johnson, Melvin Herbers, Charles Wonka, Robert Carbonell, and John Fischer.