Posmarks on An Illustrated Guide to Early 20th Century U.S. Postcards, Revised, Second Edition, by Richard W. Helbock. This 290 page generously illustrated handbook is designed to provide both an introduction to all U.S. postmarks of the 1900-1920 era and as a reference for anyone wishing to learn more about postmarks and postmark collecting. This book has been organized in 2 sections. The first section explores all U.S. postmark types found on cards and covers of the postcard era; and the second provides details of all the ways in which U.S. postmarks are collected. Part One consists of 10 chapters featuring Doane cancels, manuscript and straight line markings, Anachorisms & Mimics, machine cancels, and much more. Part 2 discusses the major ways the postmarks are collected and are arranged in 6 chapters including Geographic regions, Rural Free Delivery, Railway Post Offices, Naval & Military markings, auxiliary markings and more. A useful Glossary of philatelic history terms is included. 2002, card covers, 290 pages, New. 5½" x 8½".