Natalie Wood was the first choice to play the female lead of Prudence Bell. She had a writer friend of hers read the script and once he confirmed her fear that it wasn't up to snuff she decided it was a good time to go ahead with a tonsillectomy that she'd been putting off; the part was then given to Suzanne Pleshette.
The book that Prudence is disciplined for giving to her student is "Lovers Must Learn" by Irving Fineman, the novel this film is based upon. This was also the title used during filming.
The interior of The American Bookshop is the set of the River City Library from Warner Bros. The Music Man.