From then on he focused on history, writing biographies of Otto von Bismarck and Wilhelm II, as well as a two-volume history of the Weimar Republic.[1] From early on in his life he had admired Britain's liberal political system and his political beliefs influenced his historical work.[1][2] Eyck wrote that he was "of the Liberal persuasion" and in 1938 he wrote a biography of the Liberal politician William Ewart Gladstone, who was his ideal statesman.[3]
In the early 1940s, he wrote a three-volume biography of Bismarck.[4] According to The Times, Eyck was one of the few people to have read all the evidence concerning Bismarck's career.[1]Karina Urbach has written that as "a lawyer, Eyck despised Bismarck's lack of respect for the rule of law, and as a liberal he passionately condemned Bismarck's cynicism towards liberal, democratic, and humanitarian ideals".[4] Eyck's interpretation was criticised by Hans Rothfels and Franz Schnabel, who argued that Eyck's belief that Germany could have gone down a liberal road was unrealistic and that Germany could have been united only by Bismarck.[5]Gerhard Ritter wrote to Eyck, lamenting that his work would confirm the negative impression people abroad had of German history.[5]
Die Krisis der deutschen Rechtspflege (Berlin, 1926).
Gladstone (Erlenbach-Zürich and Leipzig: Eugen Rentsch Verlag, 1938).
Bismarck:
Volume I (Erlenbach-Zürich: Eugen Rentsch Verlag, 1941).
Volume II (Erlenbach-Zürich: Eugen Rentsch Verlag, 1943)
Volume III (Erlenbach-Zürich: Eugen Rentsch Verlag, 1944).
Die Pitts und die Fox: Zwei Paar verschlungener Lebensläufe (Zürich: Rentsch, 1947).
(English translation by Eric Northcott), Pitt versus Fox: Father and Son (London: Bell, 1950).
Das Persönliche Regiment Wilhelms II: Politische Geschichte des Deutschen Kaiserreiches von 1890 bis 1914 (Erlenbach-Zurich: Eugen Rentsch Verlag, 1948).
Bismarck After Fifty Years (London: George Phillip & Son, 1948)
(Essay published as a pamphlet by the Historical Association)
Bismarck and the German Empire (London: George Allen & Unwin, 1950).
Geschichte der Weimarer Republik, Band I: Vom Zusammenbruch des Kaisertums bis zur Wahl Hindenburgs (Erlenbach-Zürich: Eugen Rentsch Verlag, 1954).
(English translation by Harlan P. Hanson and Robert G. L. Waite), A History of the Weimar Republic. Volume I: From the Collapse of the Empire to Hindenburg's Election (Cambridge, Mass: Harvard University Press, 1962).
Geschichte der Weimarer Republik, Band II: Von Der Konferenz von Locarno bis zu Hitlers Machtubernahme (Erlenbach-Zürich: Eugen Rentsch Verlag, 1956).
(English translation by Harlan P. Hanson and Robert G. L. Waite), A History of the Weimar Republic. Volume II: From the Locarno Conference to Hitler's Seizure of Power (Cambridge, Mass: Harvard University Press, 1963).
