Since the days of Samuel Rawson Gardiner and Charles Harding Firth, no one has studied English Puritanism more thoroughly than William Haller of Columbia University. Yet Haller came to his study of the Puritans not by way of history and politics but by way of poetry. The occasion of his turning to read several thousands of Puritan sermons and tracts was John Milton. His early guides and inspirers were Professor William Peterfield Trent and Sir Herbert Grierson. His attention was also directed to this material by Sir Charles Firth. Puritan theology he learned, in the then approved Columbia University method, “by doing it.” So the man, the approach, and the method were all sufficiently unorthodox to produce a fresh study of the long-neglected sources of Puritanism.

Haller began his career as an original interpreter of Puritanism when he became a member of the editorial board for the then projected Columbia Edition of the Works of John Milton. He soon came into print with an article, “Before Areopagitica,” on the immediate contemporary background of Milton's plea for unlicensed printing. Next came his edition of the Areopagitica and other tracts for the Columbia Milton, followed by a three-volume opus, Tracts on Liberty in the Puritan Revolution, 1638-1647. Then The Rise of Puritanism appeared. Despite the turmoil of World War II, a second collection of documents, The Leveller Tracts, 1647-1653, edited by Haller and Godfrey Davies, was published. After forty-one years on the faculty of Barnard College and the graduate school of Columbia University, Haller retired in 1950 and became a fellow, later honorary fellow, of the Folger Shakespeare Library.