This document provides an introduction to service transition processes in ITIL. It discusses the key principles and purposes of various service transition processes. The processes covered include transition planning and support, change management, service asset and configuration management, release and deployment management, service validation and testing, change evaluation, and knowledge management. The overall purpose of service transition processes is to plan and manage the building, testing, and deployment of new or changed IT services to ensure they meet requirements and provide value to the business with minimal disruption.