Have a look at BushcraftUK for a great selection of free PDF books
'The 10 Bushcraft Books' by Richard Graves
This document courtesy of David B. Macpherson provides an excellent introduction to the subject of tarp shelters. He provides a wealth of valuable and useful information on their use and construction, covering everything from the most basic immediate action shelter to sophisticated structures.
U.S. Army Field Manual, No. 21-76, Survival
Bowditch -The American Practical Navigator - Free PDF's to aid your navigational skills
Metsä - Forest - Skog - Wald - A DVD about Finland's sustainable forestry: forest resources, their use and management.
FM 55-501 Marine Crewman's Handbook - Some interesting stuff can be found within this.
U.S. Army Survival Manual FM 21-76 - Includes updated versions.
Free books on Nuclear Survival - I know, a little extreme, but you might learn something new.
Wild Food Plants - A site with vids all about wild food
Our Wild Indians - Colonel Richard A. Dodge - I was looking to see if a could find a cheap copy but then found it free in pdf format. This book is quoted in the excellent book 'Nature is your guide' by Harold Gatty (you can find this in the list below). Here's the quote "The old guide Espinosa, from whom I learned the the rudiments of plains craft, told me that when he was a boy-prisoner among the Comanches, and the youngsters wished to go on a raid into a country unknown to them, it was customary for the older men to assemble the boys for instruction a few days before the time fixed for starting.
All being seated in a circle, a bundle of sticks was produced, marked with notches to represent the days. Commencing with the stick with one notch, an old man drew on the ground with his finger, a rude map illustrating the journey of the first day. The rivers, streams, hills, valleys, ravines, hidden water-holes, were all indicated with reference to prominent and carefully described landmarks. When this was thoroughly understood, the stick representing the next day's march was illustrated in the same way, and so on to the end. he further stated that he had known one party of young men and boys , the eldest not over nineteen, none of whom had ever been in Mexico, to start from the main camp on Brady's Creek of Monterey (a distance of over 380 miles as the crow flies), solely by memory of information represented and fixed in their minds by these sticks."