ITIL - The Information Technology Infrastructure Library - is a set of concepts and policies for managing IT services, developments and operations. ITIL gives a detailed description of a number of important IT practices with comprehensive checklists, tasks and procedures that any IT organization can tailor to its needs.  It was built around the W. Edwards Deming continual improvement concept of controlling and managing operations patterned on his Plan/Do/Check/Act cycle.  The goal is to align and realign IT Services to changing business needs by identifying and implementing improvements to the IT services that support the Business Processes. Improvement is the business perspective of service quality. It aims to improve process effectiveness, efficiency, and cost effectiveness of the IT processes through the whole lifecycle. To manage improvement, items to be controlled and measured should be clearly defined.