World Postmarks, by R. K. Forster.  This is a well illustrated and comprehensive work which deals with all types of cancellations. The author has 40 years of collecting experience in all aspects of postmark collecting.  The diversity and scope of international collectable material is great; as the author says, 'in postmark collecting there are no frontiers. There are only limitless horizons.' Tight binding, clean pages.  1973, hard cover, dust jacket, 192 pages, size 6" X 9", ex. lib. with usual stamps and markings.