Information security has existed as a formal discipline since the mainframe era. Infosec, as it is sometimes called, has evolved over time and has spawned a number of formal methodologies. Universities and corporate research and development have developed several security models that have been used as a design basis for access control and trust mechanisms. Written in user-friendly terms, but using a vocabulary that security practitioners also understand, this briefing will enable the reader to get to grips with security issues so they can make informed decisions on threats and risks facing their business.