Collecting antique pipes is a way of acquiring miniature works of art at reasonable cost, be they in the form of carvings in various mediums, or fine paintings on German porcelain smoking pipe bowls.
The following books by author and antique pipe aficionado Benjamin Rapaport are great points of reference for both new and established collectors:
A Complete Guide to Collecting Antique Pipes
(published 1979, reprinted 1998)
Museum of Tobacco History Art & History Guide Book
Collecting Antique Meerschaum Pipes:
Miniatures to Majestic Sculpture 1850 - 1925
The Arts of an Addiction: Qing Dynasty Opium Pipes and Accessories