Designed by Georges Peignot and first issued by Peignot & Fils in France in 1912, Nicolas Cochin was cast by various type foundries, including ATF in the United States, see this specimen from 1928. The French original didn’t include a bold style. Neither did ATF’s copy. It was added by the Caslon foundry in England, and by Ludwig & Mayer in Germany (as Fette Sonderdruck-Antiqua, 1926). McGrew mentions that Baltimore Type had a Nicholas [sic] Cochin Bold, too. I don’t know which came first, and if they were independent creations or copies.
One of these bold extensions was used for the jacket of the first edition of The Silent Witness byMelville Davisson Post (1869–1930). Published by Farrar & Rinehart in 1929 (or 1930?), the detective mystery novel was the last book by the author. Note the use of two different forms for S in the title. The forward-leaning one in “Silent” matches the one shown in a specimen for Fette Sonderdruck-Antiqua. The more upright one is the form depicted in McGrew’s glyph set for Nicholas Cochin Bold.