Career
Thorp continued the work of Julius (John) Murray Bartels, editing the fifth edition of Bartels Catalogue of the Stamped Envelopes and Wrappers of the United States and Possessions. In 1954 he completed a sixth edition and named it Thorp-Bartels Catalogue of the Stamped Envelopes and Wrappers of the United States. Thorp wrote several other books on philately: Catalogue of the 20th Century Stamped Envelopes and Wrappers of the United States, in 1968, and Complete Guide to Stamp Collecting, in 1953.
He also edited and published from 1949 to 1970 The United States. Envelope World.
