Horace Harrison was one of the preeminent philatelists in the field of British North America. Over more than 50 years he collected and researched many specialties, writing and exhibiting as his material and knowledge grew. “Canada Registered Mail: The First Twenty Years (1855 – 1875)”, a necessary companion to the four previously released Harrison Registered mail exhibit books, covers the period following the end of the Money Letter system up to the release of the first Registered Letter Stamps. The book is divided into several time-related sections for domestic Registered mail, the Pence period, followed by the Cents era, and then the Dominion period following Confederation in 1867. Separate sections illustrate international Registered letters to the United Kingdom and to the United States of America. A truly unique cross-over cover, mailed on the last day of the money letter system and delivered on the first day of the registered mail system, which shows both a money letter and a registered handstamp, was shown in the Money Letter exhibit and is the initial cover in this book. In the end it is the research and writing, the information shared, and the material assembled, that define the collector. This volume too stands as a true testimonial to Horace’s philatelic stature. It is comprehensive, and it is definitive. He had fun getting every piece, and was very pleased to know that others would be able to continue the study.“Canada Registered Mail: The First Twenty Years (1855 – 1875)” has been printed, as have been all Exhibit Series books produced since October 2002, from computer scanned originals. Digital scanning provides better defined images and allows the exhibits to be reproduced in colour or black and white. It also ensures that a lasting copy of the original is on file for later use in a variety of formats.