Designed for the mechanically curious and venturesome, this book presents descriptions and model plans for a great variety of ingenious tools, devices, and engines invented over a span of history ranging from prehistory and antiquity to the Renaissance and recent centuries. The author writes that his book "is intended for all those who like to experiment and make things work, from the schoolboy upwards. It will help them to experience the pleasure and satisfaction of making things with their own hands. "Simple instructions are given for making and putting to work models of scientific and historic significance, while suggesting their place in the advance of technical progress through the ages." Photographs of built models and drawings of historical examples animate the descriptions of some of the machines, while for each of the 35 machines a full-page scaled drawing of the model to be built is provided. Although fully adequate, these plans purposely do not specify dimensions and materials in such detail as to prelude inventiveness and machine-shop ingenuity on the part of the builder. The models are not meant to be exact, scaled duplicates of particular historical examples, but rather abstractions of their working essence. In the process of learning from experience the techniques of good mechanical craftsmanship, the model builder principles of the science of mechanics. Because they embody these basic principles in the simplest ways, most of the mechanisms described in the book are still in use, either unchanged in primitive hands, or refined and incorporated into sophisticated devices. The 35 machines are divided into six general groups: ancient machine tools, lifting devices, mechanisms, machines for pumping and water raising, blowing machines, and heat engines. Among the more famous of the machines are Leonardo's lathe, the screw generating device, the coin-in-the-slot machine, Foliot and verge escapement, the Archimedean snail, the Ctesibian pump. Hero whirling Aeolipile, and the Arabian grappling device.