That 870's all you need, Dan(G).
Hunting books may be found under Dewey Decimal System #799 in your local library, or gotten in through inter library loan.
A couple I like as literature include:
Pheasants of the Mind- Datus Proper.
Shotgunner's Notebook- Gene Hill
And any of the delightful books on bird hunting by Steve Smith.The man's a National Treasure.Great writing mixed in with stuff about why a brush gun should have more drop to the stock than a open field gun.
Joel Vance has a couple out also, with an accent on Southern hunting.
More technical works would include Keith's Shotguns, and the Orvis stuff on wingshooting. Naturally, Orvis would rather see you with a fine double like they sell.
The best way to learn, tho, doesn't come from the printed page. Find someone to take you hunting, shower them with flattery and single malt Scotch until they take you. Whine and beg if that doesn't work.
And if you cannot find,persuade, or coerce anyone, take a hunter safety course, head on out,and let the critters teach you.
Or, hit a preserve and watch the guide.
If you're close to Md, E me. Maybe I can put you in touch....
