This document provides a history of GIS from 1975 to 2011, focusing on key developments, technologies, contributors and events. It covers the commercialization of GIS starting in the late 1970s, the development of early GIS software and technologies by Esri and others, as well as significant advances in related fields like computer processing and the internet that influenced GIS. The document is intended as an informal timeline and overview, rather than an authoritative historical account.