This document provides an overview of the history of computers from early counting devices like Napier's Bones to modern computers. It begins with definitions of a computer as an electronic device that stores, retrieves, and processes data. Then it discusses several important early mechanical calculating devices and computers from the 17th century onward, including Pascaline, the Difference Engine, and Analytical Engine. It continues with later inventions like the Tabulating Machine, Differential Analyzer, and Mark I computer. The document aims to teach students the basic concepts of computers and discuss the history leading to modern programmable digital computers.