Shelters, Shacks, and Shanties by Daniel C. Beard

Shelters, Shacks, and Shanties is a book written by Daniel Carter Beard in the early 1900s. It covers the subject of wilderness shelters. The types of shelters covered vary from simple debris shelters to much more complex permanent camps.

The instructions are not detailed, and same of the shelters pictured would be very difficult for the average woodsman to construct in a short period of time, following just the instruction in the book. With time and practice however, the ideas that can be obtained from this book, can significantly improve your improvised shelters.

As far as I know, this manual is in the public domain. A copy can be obtained here, here, and many other places online.