This document summarizes the five generations of computers from the 1940s to present. The first generation used vacuum tubes for storage and were large, power-intensive machines. The second generation introduced transistor-based computers with magnetic core storage. The third generation saw the rise of integrated circuits, making computers smaller, cheaper, and more powerful. The fourth generation began in 1971 and utilized very large scale integration and microprocessors. The fifth generation, starting in the present, uses externally large scale integration and parallel processing, with a goal of artificial intelligence and knowledge-based systems.