What book most informed your backpacking technique?

While my backpacking experience is, admittedly, limited; I feel like virtually everything I do outdoors is cut and Paste from Mountaineering: The Freedom of the Hills.

Check book

After a lot of hands-on experience there was still a lot for me to learn (of course I didn't know what I didn't know), and after picking up the Backpacker's Field Manual I can honestly say that single book was so dense with knowledge that I have to put it at the top in terms of skills. Additionally, there's quite a few online resources that are available for use in conjunction with the book (packing lists, how to organize a hiking group, etc).

Honestly, though I had and devoured repeatedly two or three books on backpacking and wilderness living as a kid, my actual skills mostly came from doing it, early on in the company of more experienced hikers. I already knew a lot about car-camping from family vacations, and we did a couple of memorable BP trips when I was in grade school, confirming my yen to get out and do more. But, like I say, I learned most of what I know from guys like Trapper and Shools and some others who let me tag along when I was in grad school.

Then I found this place and learned about UL and FBC, and learned a whole bunch more.

That's a great book, although most of it is waaay beyond what I do on backpacking trips.
I used to to a little (casual) mountaineering, but have just been mostly backpacking in recent years.

To make that determination I reviewed my book shelf and selected the backcountry book in poorest condition.

The A.M.C. White Mountain Guide 1972

This is the book that started it all and facilitated my Active/Reflective learning preference of processing information on the go.

I started with a 1950 hard bound 1,100 page Boy Scout manual. I followed the instructions to sew my first pack, as well as the instructions on how to made a wooden frame. My survival kit fit into a Band-Aid can. I learned how to make wooden fishhooks, snares, figure 4 dead falls, plants to eat out in the woods, fillet a fish, skin a rabbit, tan the skin, sharpen a knife, bake Bannok bread on a stick, 20 ways to build a camp fire and when to use each way, how to use a compass, read a topo map and where to get topo maps from, how to build stuff with a hand axe and buck saw, not to put the latrine up stream from the camp and much more from that book.

ETA: I made wooden fish hooks, than tied a fly with my hair onto the wooden fish hook, and caught fish.