The original version of ITIL was a manual published in the 1980s to help government IT departments in the United Kingdom establish a framework for best practices. While ITIL v2 remained strongly focused on basic IT operations, ITIL v3 emphasizes the concept that IT is a service that supports business goals.
The ITIL v3 framework is broken into five sections:
ITIL service strategy - specifies that each stage of the service lifecycle must stay focused upon the business case, with defined business goals, requirements and service management principles.
ITIL service design - provides guidance for the production and maintenance of IT policies, architectures and documents.
ITIL service transition - focuses upon change management role and release practices, providing guidance and process activities for transitioning services into the business environment.
ITIL service operation - focuses upon delivery and control process activities based on a selection of service support and service delivery control points.
ITIL continual service improvement - focuses upon the process elements involved in identifying and introducing service management improvements, as well as issues surrounding service retirement.
IT professionals can be accredited under four levels for ITIL v3: Foundation, Intermediate, Expert and Master. The Foundation level covers the terminology and basic concepts of ITIL as a whole, while the higher levels go into greater depth for each of ITIL's five major topics.