This document summarizes the five generations of computers from 1945 to the present. The first generation used vacuum tubes and were very large, expensive, and unreliable. The second generation used transistors, which made computers smaller, more reliable, and efficient. The third generation used integrated circuits, making computers faster, cheaper, and more compact. The fourth generation began with microprocessors, resulting in smaller and more powerful personal computers. Current and future computers are exploring fifth generation technologies like artificial intelligence, natural language processing, and quantum computing.