Marjory Sente's Collecting First Day Covers on-line study course traces the history and development of First Day Cover collecting and goes into detail regarding the cachets and cancellations found on FDCs.
The free course appears on the American Philatelic Society's Stamp Campus website. There is no cost to take the course which consists of nine lessons. At the end of each lesson there are some short assignments.
Individual lessons cover an introduction to FDC's, history of FDC collecting, history and types of cancellations, types of cachets, techniques for identifying cachets, developing a specialized collection, more ways to collect FDCs, and care of your FDC collection. Various ways to collect and exhibit First Day Covers are also included.
Shown above, first use in 1937 of the "First Day of Issue" machine slogan cancellation.
To take the course, click here.