ACKNOWLEDGMENTS 
I wish to acknowledge my indebtedness to the following 
persons for assistance of various kinds in the preparation 
of this book: 
To Dr. Chas. C. Adams, lately Director of the Roosevelt 
Wild Life Forest Experiment Station, N. Y. State College 
of Forestry, Syracuse, now Director of the New York 
State Museum, Albany, for permission to use notes made 
when studying the beaver in the Yellowstone National 
Park, and in the Longs Peak Region, Colorado. It was 
while making these studies that I first thought of writing 
this book, so that it is in part a by-product of that work, 
and Doctor Adams has given me every encouragement 
while I have been preparing the manuscript. He also 
gave me permission to use the photographs reproduced in 
figures 2, 14, 18, 19, 20, 23, 24, 25, 27, 28, 31, 34, 35, 37, 
38, 39, 40, 41, 45, 48, 49, 50, 54, 55, 56, 58, 60, 61, 62, 
63, 64, 65, 66, 67, 70, 71, 72, 74, 75, 76 and 78. Also to 
use the maps and plans reproduced in figures 15, 16, 17, 
29 and 30. 
Joseph Dixon, of the Museum of Vertebrate Zoology, 
Berkeley, California, has kindly supplied me with much 
helpful information concerning the breeding habits of the 
beaver in California. 
Dr. William Lyman Underwood, of the Massachusetts 
Institute of Technology, has given me information about 
the influence of beaver ponds on fish. 
The Rocky Mountain News, Denver, Colorado, gener- 
ously gave permission to use the picture of the young 
beavers in the lodge. 
