Humanity's hunt for calculating devices probably started with the use of small pebbles to keep track of numbers. The counting inventions progressed through the abacus, early mechanical calculators, and other ingenious devices culminating in today's computers. In this new book, Thomas Russo chronicles 600 years of caculating devices, providing valuable information for historians and collectors alike. Stretching from ancient times to the earliest computers, this book provides an insight into breadth and depth of human creativity and drive. With 500 color photographs, descriptive captions, and a guide to current values, this is an essential guide in a field that is finding ever more enthusiasts.