This handbook is published in support of the National Park Service's management policies and interpretive programs at the park. Part 1 places the park in its historical setting--the 19th-century canal era--and tells how citizen initiative eventually saved it from highway building. Part 2 explains how the canal was built, how it worked, who made it work, and what it contributed to developing agriculture, mining, and industry in the Potomac River basin. Part 3 presents concise travel guide information, detailed canal maps, and other reference materials to help you make the most of a visit to the canal.