Up to the time of Benjamin Franklin's appointment as Postmaster of Philadelphia, in 1737, letters were held at a post office until called for. Desirous of improving the system, Franklin began the publication of names of persons for whom unclaimed letters were in the office under his jurisdiction. The first list appeared in Franklin's Pennsylvania Gazette of 21 March 1738 and, as a result, the addressees, their friends, or messengers, picked up much of the mail. These lists, which were printed from time to time throughout the colonial period, provide a wealth of genealogical information by locating thousands of individuals at various times and, upon occasion, identifying their trade, profession, or military rank. Sometimes The Gazette published lists from towns other than Philadelphia, specifically Chester, Lancaster, Trenton, New Castle, and Wilmington.The present volume--an innovative and ingenious tool for genealogical research--contains the names of approximately 27,000 persons whose letters lay unclaimed in the post offices of the above towns. All lists printed in The Gazette from 1748 throughout the colonial period are here published, with the names arranged alphabetically. Lists previous to 1748 appear in Mr. Scott's "Abstracts from Ben Franklin's Pennsylvania Gazette, 1728-1748."