A Line to Kill by Anthony Horowitz
Upon meeting the fictional character Anthony Horowitz, the husband of a blind woman helpfully describes the writer out loud to his wife: “Dark hair, untidy, going grey. Jewish. Didn’t shave this morning.” Horowitz, who bears an uncanny resemblance to the author of A Line to Kill, tries hard not to be offended.
This is the third book of a series in which the fictional Horowitz—let’s call him Tony for clarity—teams up with former police detective Daniel Hawthorne to investigate and subsequently write about a murder. Hawthorne is the uncontested star of the partnership, with Tony resigned to his Watsonian role as chronicler of the idiosyncratic detective’s exploits.