Oooh, thank you! I had heard of "The Cinderella Book" before, but hadn't looked into it. Seems especially promising given the title that came before it:

> The first edition in turn constituted a major revision of a previous textbook also written by Hopcroft and Ullman, entitled Formal Languages and Their Relation to Automata.

https://en.wikipedia.org/wiki/Introduction_to_Automata_Theor...

Used copy ordered.

Searching for that title also lead me to _Introduction to Formal Languages_ by Gyorgy E. Revesz, which also looks like a good fit and which Dover is currently printing as one of their reasonably-priced paperbacks!