The rise of collectibility of slide rules has been a phenomenon that has confounded even the most knowledgeable antique tool collectors. Now, in this important new book, author Peter Hopp unlocks the mysteries of slide rules and lays out the fascinating history of calculation in a way that expands the knowledge of the advanced collector and also brings the novice up to speed. Included is a thorough history of slide rules, biographies of important figures, patent information, important innovations and much, much more. An important new reference.