A Cult Classic?
Been spending some time in some older books, and revisited one I think is vastly underrated: The Soviet Chess Conveyor, by Mikhail Shereshevsky. The translation is terrible, but there’s a lot of good material there just waiting to be dug up.
Recommendation: This book is not for beginners. It has philosophical advice that is excellent for coaches/teachers, and has some interesting analysis of opening/middlegame positions that I suggest you double-check before you playing. (You do double check all analysis before you play it, don’t you?)