Samuel Hartlib was a key figure in the intellectual revolution of the seventeenth century. Originally from Elbing, in Prussig, Hartlib settled permanently in England from the late 1620s until his death in 1662. His aspirations formed a distinctive and influential strand in English intellectual life during those revolutionary decades. This volume reflects the variety of the theoretical and practical interests of Hartlib's circle and presents them in their continental context. The editors of the volume are all attached to the Hartlib Papers Project at the University of Sheffield, a major collaborative research effort to exploit the largely untapped resources of the surviving Hartlib manuscripts. In an introduction to the volume they explore the background to the Hartlib circle and provide the context in which the essays should be read.