Multiplication is vital to the conduct of commerce but is time-consuming and error-prone. Many aids were developed over two centuries to address these issues. This article surveys the development of the most widely used of these, the ready reckoner. The underlying principles of reckoner design are explained. To explain their range of use, over 1,250 entries from the major national library catalogues and elsewhere have been classified by application, target user, date, price and format. A sample of different styles are illustrated.
['Bruce O. B. Williams', 'Roger G. Johnson']
Ready Reckoners