Hartlib, Samuel an English writer of the 17th century, was born of Polish Protestant parents. He came to England about 1640, took an active part in the theological questions of the day, and endeavored to bring about a union of the different churches. He afterwards devoted himself to the improvement of agriculture, etc. Having spent all his fortune in these attempts, he received from Cromwell a pension of £300, which was suppressed at the Restoration. He spent the latter part of his life in retirement, and perhaps in want. The exact time of his death is unknown. He wrote A Relation of that which hath been lately attempted to pro-cure Ecclesiastical Peace among Protestants (Lond. 1641). — Considerations concerning England's Reformation in Church and State (1647, 4to): — Twisse's doubting
conscience resolved (1652, 8vo); some works on Husbandry, etc. Milton addressed his Essay on Education to Hartlib. See Gentleman's Magazine, 72; Censura literaria, vol. 3; Chalmers, General Biographical Dictionary.