This series documents Litchfield's publication, research, and writing activities during his career as founding editor and publisher of Olearius Editions, and includes business correspondence, accounts, drafts, proofs and notes for Litchfield's publications on oil mills, the oil industries, and oleomargarine stamps. Among the notes are early diaries and accounts (both originals and photocopies) for the Moravian Oil Mills at Bethlehem and notes and drawings on other oil mills around the world. There are also programs and papers of professional conferences on fats and lipids, mills, and industrial archeology. The subseries of American Oil Mills and Foreign Oil Mills are comprised almost entirely of binders containing research material collected by Litchfield.