This document discusses the history and evolution of cloud computing, including its origins in concepts like virtualization, supercomputing, cluster computing, grid computing, and distributed computing. It traces the development of these technologies over time, from early concepts in the 1960s proposed by John McCarthy regarding computation as a public utility, to modern implementations like Google's large network of clustered commodity servers. Key people and technologies that advanced each concept are described, such as Seymour Cray's work in supercomputing and Ian Foster and Carl Kesselman's contributions to grid computing through projects like Globus Toolkit.