PREFACE ix 
passages from “What is Capital?” 1897, “Senses of 
Capital,” 1898, and “The Role of Capital in Economic 
Theory,” 1898, and to the Quarterly Journal of Economics 
for similar permission with reference to * Precedents for 
Defining Capital,” 1904. 
I wish also to express my obligations to the many 
persons who have aided me in the preparation of this 
work, among them especially my wife; my brother, Mr. 
Herbert W. Fisher; my colleagues, Professor Henry C. 
Emery, Professor John P. Norton, and Dr. Lester W. 
Zartman; and my friends, Mr. Richard M. Hurd and 
Mr. Orland S. Isbell of New York City. 
IRVING FISHER. 
New Haven, CoNN., June, 1906.