Atlas Chemical Industries, Inc. was a chemical company based in Wilmington, Delaware. This small collection consists of pictorial envelopes produced by Atlas Chemical Industries, Inc., along with promotional inserts, that were collected by Atlas research pharmacist Matthew J. Lynch from 1963 to 1986. Atlas Chemical used these envelopes for promotional mailings to industry professionals; their illustrations complement special edition postage stamps, issued and postmarked on their first day of circulation. They depict a range of topics, including landmark anniversaries, commemorations, famous people, notable events, elements of nature, and aspects of American life.