I'm seeking recommendations for a book to buy for my philosophy teacher, who is leaving my sixth form at the end of this year, so I would quite like to give him a gift as thanks for his talented teaching.
I know he studied philosophy at university (and has been teaching for upwards of 10 years), so I don't want book recommendations of fairly common prescribed texts nor of any textbooks (unless remarkably written). Furthermore, he is remarkably clear at explaining difficult to understand concepts, so I anticipate he will have read quite widely and so recommendations which are less commonplace but still highly interesting would be appreciated.