For more information about Active Directory Service Interfaces and the technologies on which they are based, you may find the following sources helpful.
The Active Directory Service Design Specification Version 2.0
The Component Object Model Specification
Understanding ActiveX and OLE, by David Chappell, Microsoft Press, 1996.
OLE 2 Programmer's Reference, Volume Two, Microsoft Press, 1994.
Inside OLE, 2nd edition, by Kraig Brockschmidt, Microsoft Press, 1995.
Inside COM, by Dale Rogerson, Microsoft Press, 1997.
Microsoft's OLE DB Programmer's Reference Version 1.0, 1996.