The Information Technology Infrastructure Library (ITIL) is a collection of best practices that aim to improve and then maintain a certain level of computing services quality in the information technology sector. ITIL covers organizational structure and skill requirements for an IT organization via a comprehensive set of procedures with which an organization can manage its IT operations. These procedures do not rely on a particular vendor’s technology and apply to all aspects of IT infrastructure.

ITIL consists of a collection of 7 books. The sets are sub-divided into disciplines, each of which is focused on a specific subject.

1. Service Delivery: Covers the processes required for the planning and delivery of quality IT services, and looks at the longer-term processes associated with improving the quality of IT services delivered.
   1. IT Financial Management
   2. Capacity Management
   3. Availability Management
   4. IT Continuity Management
   5. Service Level Management
2. Service Support: Describes the processes associated with the day-to-day support and maintenance activities involved in the provision of IT services.
   1. Change Management
   2. Release Management
   3. Problem Management
   4. Incident Management
   5. Configuration Management
   6. Service Desk
3. Planning to Implement Service Management: Examines the issues and tasks involved in planning, implementing, and improving service management processes within an organization; also addresses the issues associated with addressing cultural and organizational change, the development of a vision and strategy, and the most appropriate method of approach.
4. Security Management: Details the process of planning and managing a defined
   level of security for information and IT services, including all aspects of security incidents. Also includes the assessment and management of risks and vulnerabilities and the implementation of cost-justifiable countermeasures.
5. Information and Communications Technology (ICT) Infrastructure Management: Covers all aspects of ICT infrastructure management from identification of business requirements through the procurement process, to the testing, installation, deployment, and ongoing operation and optimization of ICT components and IT services.
   1. Network service Management
   2. Operations Management
   3. Management of local processors
   4. Computer installation and acceptance
   5. Systems Management
6. The Business Perspective: Provides advice and guidance to help IT personnel understand how they can contribute to business objectives and how their roles and services can be better aligned and exploited to maximize contribution.
7. Application Management: Describes how to manage applications from the initial business need through all stages in the application lifecycle, up to and including retirement. Places emphasis on ensuring that IT projects and strategies are tightly aligned with those of the business through the application lifecycle, to ensure that business obtains the best value from its investment.

From the beginning, the ITIL framework has been publicly available (however, it is copyright protected). This means that any organization can use the framework described by the OGC in its numerous books. Because of this, ITIL guidance has been used by a wide range of organizations including government, energy, public utilities, retail, finance, and manufacturing. Very large organizations, very small organizations and everything in between have implemented ITIL processes.