This document discusses computer system security and provides information on various topics related to ensuring security. It begins with an introduction to computer security, including internet security, remote sharing, and software installation. It then covers operating system security focusing on access control, supervision, and resource allocation. Statistics on world internet usage and computer penetration rates are presented. The document goes on to discuss external interface security, internal security, surveillance, threat monitoring, access controls, cryptography, viruses, worms, trojans, spyware, specific spyware programs, internet security software options, firewalls, and phishing prevention. Recommended resources on these security topics are listed at the end.