The New Cyclopaedia; or, Universal Dictionary of the Arts and Sciences was edited by the Revd Abraham Rees and written by about 100 contributors with specialist knowledge. It appeared in parts between January 1802 and August 1820, and ran to 39 volumes of text (containing about 39 million words), five volumes of engraved plates, and an atlas. An American edition was published by Samuel Bradford of Philadelphia between 1806 and 1822, with additional American material. The articles covered the arts and humanities, agriculture, science, technology, and medicine. They remain a particularly important source of information about the technological processes of the period.