1. An automated method is disclosed for building information technology services from a library, comprising: presenting source entities in a library for user selection as service modeling entities, wherein the source entities have initially predefined properties for service modeling; an automated computer process copying user selected ones of the source entities from the library into a computer readable storage medium providing a services layer, wherein the copying generates instances in the services layer of the selected service modeling source entities, such that the services layer instances at least initially include the initially predefined properties of their respective source entities; and the automated computer process maintaining the properties of the selected ones of the source entities, including maintaining the selected source entities' properties independently of changes made in a first change mode to the properties of the service modeling entity instances in the services layer, so that the user may change the properties of the service layer service modeling instances, wherein if the change is in the first change mode, the selected source entities continue to be available in the library with their respective initially predefined properties for still more user selection as service modeling entities.