Story in two parts of 9.67 and 5.67 pages.
The Joker impersonates four famous silent movie comedians: the Tramp is Charlie Chaplin, Deadpan is Buster Keaton, Cross-eyes is Ben Turpin, and Specs is Harold Lloyd. His last impersonation is of Harpo Marx who became famous in the sound era, not the silent era, despite the fact that he never uttered a word onscreen.
This story formed the basis for the 1966 Batman TV episodes "Death in Slow Motion" and "The Riddler's False Notion", using The Riddler instead of The Joker.
Credits for script, pencils and inks confirmed from Julius Schwartz's editorial records, provided by DC Comics.
Letters from Dick Ruprecht, Guy H. Lillian III, and Andrew Ice. On final interior page of the comic. Top half of page.