This document provides an overview of the history and evolution of information security. It begins by covering the origins of computer security during World War II to protect early mainframes. It then discusses the development of ARPANET in the 1960s and the early internet in the 1970s/80s, when security was initially neglected. The document outlines the continuing growth of networks and interconnected systems in the 1990s to present day and the importance of securing these environments. It introduces some core concepts of information security including definitions, critical information characteristics, and the systems development life cycle approach to implementation.