Books mentioned in Devil's Cub by Georgette Heyer. Some books contain oodles of titles. This one has 2:
The Inflexible Captive by Hannah More, a play.
The Pythagorean Diet, or Vegetables only conducive to the Preservation of Health and the Cure of Diseases, by Dr. Cocchi. Amazon.com gives the title as: The Pythagorean diet, of vegetables only, conducive to the preservation of health, and the cure of diseases. This seems to be a translation (from Itailan) of a transcript of a lecture on Pythagoreanism and would probably have been published as a pamphlet.
Both appear to be included as sources of humour.