In each of the AARs from the Scout Course I get questions on additional reading for the Small Unit and what books have went into my own personal development. Contrary to popular belief, field manuals are only going to get you so far- they’re written to be a companion reference to actual courses and have a context to them. There’s a lot left out- especially in the ‘why’ department. And the people who usually hold them up saying “this is all you need!” is usually some dumbass who’s never actually done it.
That said, here’s some of the books I’ve brought up off the top of my head and a few that I remembered after a few beers:
Guerrilla Sniper Tactics Handbook
Tom Brown’s Field Guide to Nature Observation and Tracking