I found someone selling this, so I went looking for a free copy. Since it was created by the US military, it is not under copyright.
You can find it as one PDF file here:
http://www.equipped.com/multiservice...anual_1999.pdf
Or you can download the individual chapters here:
http://www.equipped.com/fm21-76.htm
P.S. This isn't just a wilderness manual, it's about _survival_. If you are unsure of the difference, read Appendix A.