Buy used from: $0.19
Understanding land navigation by map and compass is probably one of the most fundamental skills a person should know unless the entire life is going to be spent in urban areas.
Buy used from: $0.99
This one and the next are merely supplements to the first. If you find you enjoy this sort of thing you'll be buying every book on the subject you think will help you.
Buy new: $13.57
/ Used from: $4.63
This one is for those who truly got excited about the first two.
Buy used from: $42.00
A nice addition to the library of the backpacking veteran.
Buy new: $12.21
/ Used from: $10.21
If you plan to spend time in the desert and haven't done so previously, learn as much as you can assimilate about it ahead of time.
Buy new: $11.53
/ Used from: $8.24
This one's general. Gives a lot of advice on a subject we all hope for. A little knowledge can sometimes go a long way.
Buy used from: $2.56
If you've done a lot of backpacking you don't need this. If you haven't, you might.
Buy new: $19.80
/ Used from: $12.69
These can be helpful, though they tend to all discover the same places.
Buy new: $13.57
/ Used from: $12.40
Get the ones for where you are and where you are going to be
Buy used from: $74.18
A supplement to Delorme, not a replacement
Buy used from: $12.98
Roadside stuff. My list on Trekking Suggestions will give you more help for back country.
Buy used from: $4.52
I love these places. Unfortunately the ones in books mostly aren't ghost towns anymore.
Buy new: $18.00
/ Used from: $0.33
Get one for where you are and where you are going
Buy new: $12.24
/ Used from: $4.75
A good overview. Same as above
Buy used from: $0.35
The BLM is finally beginning to put out information about their (our) wilderness areas. This one's a good bang for the buck.
Buy new: $29.95
/ Used from: $3.69
If you depend on a 4 wheeler to get you to a warm place before dark you are probably going to wish you had this book someday.
Buy used from: $5.38
I'd say pick one or three of these kinds of guides, depending on how much time you intend to spend in an area.
Buy used from: $3.24
The nice thing about this kind of book is that you tend to only have a 50-75 percent overlap in the info they provide.
Buy used from: $1.73
This one will lead you on some merry chases.
Buy new: $6.95
/ Used from: $3.88
You might think you don't need this book. If you've been in the woods a lot you are probably correct.
Buy used from: $0.53
You can figure it out on your own, but if you are the kind of person who likes to have some help this book will give you a good feel for the ins and outs of the GPS.
Buy new: $66.00
The best outdoors hat in the western world, bar none. It's in my trekking and other lists, also.
Buy new: $106.40
/ Used from: $95.00
Shop around on these. This one's good, but if you need something less fancy there are Magellans on the market with more economy. Some are listed on Amazon.
Buy new: $18.96
/ Used from: $17.30
Lots of prospecting, treasure hunting and survival lore you won't find anywhere else.