Volume 1, The Early Years: 1879-1902

Volume 2, The Swiss Years: Writings, 1900-1909

Volume 3, The Swiss Years: Writings, 1909-1911

Volume 4, The Swiss Years: Writings, 1912-1914

Volume 5, The Swiss Years: Correspondence, 1902-1914

Volume 6, The Berlin Years: Writings, 1914-1917

Volume 7, The Berlin Years: Writings, 1918-1921

Volume 8, The Berlin Years: Correspondence, 1914-1918 (in two parts)

Volume 9, The Berlin Years: Correspondence, January 1919-April 1920

Volume 10, The Berlin Years: Correspondence, May-December 1920, and Supplementary Correspondence, 1909-1920

Volume 11, Cumulative Index, Bibliography, List of Correspondence, Chronology, and Errata to Volumes 1-10

Volume 12, The Berlin Years: Correspondence, January-December 1921