“ Most of Clarke’s earlier published writings were addressed to the immediate need of establishing a larger theory of religion than that espoused by people who were still trying to be Calvinists, people who maintained what a good American phrase calls “hard-shelled churches.” But it would be wrong to call his work controversial. He was always declaring that the business of the Church is Eirenic and not Polemic. Such books as Orthodoxy: Its Truths and Errors (1866) have been read more largely by members of orthodox churches than by Unitarians. ”

“ He published but few verses, but at the bottom he was a poet. He was a diligent and accurate scholar, and among the books by which he is best known is one called Ten Great Religions (2 vols., 1871–1883) . ”