Conklin, Groff, The New Republic Anthology 1915-1935, Dodge Publishing Co., 1936.

The New Republic Anthology is a collection of the best essays from the first two decades of the periodical founded by Herbert Croly. The book includes a wide array of political and social commentary, as well as providing a great snapshot of the time period.

Fink, Leon, Major Problems in the Gilded Age and the Progressive Era, D.C. Heath & Co., 1993.

This book combines primary source documents with commentary about the issues facing America from 1887 to 1920.

Forcey, Charles, The Crossroads of Liberalism, Oxford University Press, 1961.

Forcey profiles three political journalists of the progressive era: Herbert Croly, Walter Weyl, and Walter Lippman.

Olson, James S., Encyclopedia of the Industrial Revolution in America, Greenwood Press, 2001.

This reference book offers in-depth coverage of the economic, political, and social developments of the Industrial Revolution in the United States from 1750 to...