In this chapter, we examined the support ATL provides for building fully functional COM servers in DLL and EXE modules. Registration is simplified by using Registry script resources and the Registrar component. Class objects are implemented in CComClassFactory for all object types, with unique creation functions provided through typedefs. Creator classes are used as object factories for both class objects and the target objects themselves. The object map is maintained as a collection of object information that can be iterated to locate specific registration and activation methods for all classes of objects or a specific object class. ATL effectively handles module locking to control server lifetime in DLL and EXE housings.