THE ITIL CORE
The service lifecycle is an approach to IT service management that empha-
sises the importance of coordination and control across the various functions,
processes and systems necessary to manage the full lifecycle of IT services. The
service management lifecycle approach considers the strategy, design, transition,
operation and continual improvement of IT services. The service lifecycle is
described in a set of five publications within the ITIL Core set. Each of these
publications covers a stage of the service lifecycle (see Figure 1.2) from the
initial definition and analysis of business requirements in service strategy (SS) and
service design (SD), through migration into the live environment within service
transition (ST), to live operation and improvement in operation (SO)
continual service improvement (Csi). The term "continual is used in preference to
"continuous' to emphasise that this activity is not performed on a constant basis,
but as a series of planned and controlled actions.