ABSTRACT
This book grew out of an article entitled “The Big Change” which I wrote in the spring of 1950 for the Centennial Number of Harper’s Magazine, published in October, 1950; which in turn drew upon the text of a talk I had given on “Social Changes of Our Time” before the Pennsylvania Historical Society on February 4, 1949, which was printed in The Pennsylvania Magazine of History and Biography, April, 1949. My Centennial article dealt with the changes in the United States between 1850 and 1950, with special attention to the distribution of wealth and opportunity; after it appeared, I decided to develop this theme in book form, but to concentrate upon the period between 1900 and 1950, which offered, it seemed to me, a more significant contrast than did the longer period.
