Samuel Hartli(e)b (ca. 1600 – 10 March 1662) was a German-British polymath. An active promoter and expert writer in many fields, he was interested in science, medicine, agriculture, politics, and education. He settled in England, where he married and died. He was a contemporary of Robert Boyle whom he knew well, and a neighbour of Samuel Pepys in Axe Yard, London in the early 1660s.
Hartlib is often described as an "intelligencer", and indeed has been called "the Great Intelligencer of Europe". His main aim in life was to further knowledge and so he kept in touch with a vast array of contacts, from high philosophers to gentleman farmers. He maintained a voluminous correspondence and much of this has survived, having been lost entirely from 1667 to 1945; it is housed in a special Hartlib collection at the University of Sheffield in England. He became one of the best-connected intellectual figures of the Commonwealth era, and was responsible for patents, spreading information and fostering learning. He circulated designs for calculators, double-writing instruments, seed-machines and siege engines. His letters, in German, Latin, English and other languages, have been the subject of close modern scholarship.
Hartlib set out with the universalist goal "to record all human knowledge and to make it universally available for the education of all mankind." His work has been compared to modern internet search engines.