Abstract: Research papers of Herbert F. Margulies related to his biography of Irvine L. Lenroot, a Wisconsin legislator, Republican Senator, and Progressive political associate of Robert M. La Follette. The files consist of Margulies' research notes, considerable correspondence with Lenroot's daughter, Katharine Lenroot, and a typescript copy of the unedited version of the biography entitled Progressivism, Patriotism and Politics: The Life and Times of Irvine L. Lenroot. Also included is additional correspondence and writings of Margulies concerning the progressive movement in Wisconsin.