Originally developed in 1993 for an auction of an Architect's private collection of over 1,500 drawing instruments and calculators; this extensive book is one of a few comprehensive references available for comparative study of these instruments. The original collection was assembled over a twelve year period from sources in the US and Europe. Each instrument is listed in a scientific format for comparative evaluation and identification. An abbreviations table supports this approach. Profusely illustrated with 113 color photos and 61 highly organized text pages. The Subject Index has over 400 individual references dissecting this impressive collective of instruments from the 18th C. thru the mid 20th century. Instruments are categorized by Maker, Country, Period of Manufacture and function. Different instrument makers and suppliers are referenced to over 300 individual items. The four page Table of Contents provides a logical and extremely useful subjective summary of the catalog contents so that whatever the instrument or drawing tool, its location can be easily found. The photographs were taken with the idea of showing these important instruments in a comparative array. Researchers and collectors will find this a valuable resource. These instruments represent a most prolific period of time in our history of invention and advancements in technology. Computers are the new tools which demand a new pace of design and documentation.... They leave behind the centuries of drawing instruments that were the connection from the hand to the paper.