Authoritative is a very tall order. Bismarck is a very polarizing figure both in German history and in German politics. Bismarck himself contributed greatly to muddying the waters through his memoirs and zealous control of the narrative of his own life while he was alive. With this in mind, it is important to look at the spectrum of Bismarck biographies rather than one single book.

Both Edgar Feuchtwanger and Katahrine Lerman's biographies are good, focused introductions to the great man. Even though it is quite old and its psychohistory methodology is very dicey, AJP Taylor's Bismarck: The Man and Statesman explores these contradictions and is one of Taylor's best-written works. Jonathan Steinberg's Bismarck: A Life is a more modern approach towards Bismrack's sometimes divided nature, and Steinberg tends to have a more negative appraisal of the Iron Chancellor than some biographers. Henry Kissinger's 1968 Daedalus essay "The White Revolutionary: Reflections on Bismarck" is also interesting reading and important to getting a handle on the post-1945 view of Bismarck.

German authors nor surprisingly have their own biographies of Bismarck. Otto Pflanze's multi-volume biography focuses upon high politics and unification. Lothar Gall's two-volume biography (Bismarck: The White Revolutionary ) takes its cues from Kissinger and is an appreciation of Bismarck from a center-right perspective. In contrast, Erich Eyck's Bismarck and the German Empire hews to a much more negative assessment of Bismarck's politics and legacy on modern Germany.