[sufue]

Curtains for Three is the 18th in the Nero Wolfe/Archie Goodwin series by Rex Stout. It has dropped to $2.99 at Kindle and Kobo US, and £1.49 at Kindle UK. This is the Bantam version. There is also a less expensive $1.99 version published by Caramna Corporation available - I'm not sure if this is a "hinky" version or not. If anyone knows anything more about Caramna, it would be nice to know. A quick search wasn't particularly enlightening.

In any case, for the Bantam version:

Kindle US: https://www.amazon.com/Curtains-Thre...dp/B003JMFP1K/
Kobo US: https://www.kobo.com/us/en/ebook/curtains-for-three
Kindle UK: https://www.amazon.co.uk/Curtains-Th...dp/B003JMFP1K/

Spoiler:

In these three baffling mysteries of motive and murder, even the great Nero Wolfe finds himself stumped. First there is the case of the two passionate lovebirds who want to make sure that neither is a cold-blooded killer. Then it’s off to the races, where Wolfe must choose from a stable of five likely suspects to corral a killer on horseback. And finally the detective finds himself the confidant of a distraught, self-described grifter who claims a murderer is stalking Wolfe’s own brownstone. Through brilliant deduction is determined to expose the truth behind the veils of illusion—and bring down the curtain on three all-too-clever murderers.