Look at the spine of _Threats_and_Other_Promises_ ... Notice anything strange about the author's name?
In Gene Wolfe's _The_Fifth_Head_of_Cerberus_ the protagonist (several hundred years in our future) is looking for a book on flight. He picks up a musty old book in the library, but it turns out to be a collection of Vernor Vinge's short stories - he was misled by the the two Vs in the name on the spine overlapping to form a W. (There's also an oblique reference to Kate Wilhelm's _The_Mile-Long_Spaceship_ in the same paragraph.)
Wolfe's novella was written *before* any of Vinge's stories were collected into a book. Vernor was amused by the idea, and deliberately asked the publisher to print the name this way. Check out the book's dedication ...
s: promise of the Singularity. S: Existence of the Singularity fairly prominent in some way. A: anarchist