Correspondence and Conversations of Alexis de Tocqueville with Nassau William Senior from 1834-1859, ed. M.C.M. Simpson, in Two Volumes (London: Henry S. King & Co., 1872). 2 Vols. http://oll.libertyfund.org/titles/2445,
A two volume collection of journal entries and letters between Tocqueville and Nassau Senior between 1834 and 1859. Vol. 1 contains material from 1834 to 1851. Vol. 2 contains material from 1851 to 1859.
The text is in the public domain.