The 'return of the Turks': the campaigns of 1871-73 and the context of Tanzimat imperialism -- Imperial visions : knowledge production, empire, and the creation of difference, 1849-75 -- 'According to their customs and dispositions' : elaborating politics of difference in Ottoman Yemen, 1874-91 -- Struggling for a righteous order : the rise of the Zaydi imams and the reconfiguration of difference, 1890-1908 -- An imperial borderland as colony? the Da"an agreement and the reaffirmation of colonial Ottomanism, 1905-19.