Key Element Guides are handy reference guides to the core ITIL titles: Service Strategy, Service Design, Service Transition, Service Operation and Continual Service Improvement. The Key Element Guides discuss ITIL, its evolution and the need for the Service Lifecycle approach. They examine what is meant by best practice framework, how this relates to 'common practice', and about degrees of prescription and what compliance means. Each book provides an overview of the key elements, principles and objectives of the core ITIL title it examines.