Writing Device Drivers for Windows is an entirely different discipline from traditional Application Programming. Device Drivers are Operating System extensions. In order to extend the OS effectively, a developer needs to understand many of the detials of the Operating System's architecture and its working. In addition it is necessary to learn the device driver development environment and kernel mode debugging. Windows Driver Model (WDM) is an enhanced form of the NT 4 kernel-mode device driver model. The main structural changes are the addition of Plug and Play (PnP), Power Management, Windows Managment Instrumentation (WMI) and Device Interface support. These features are included in these course notes, along with the details of the necessary development environment. These course notes impart the knowledge and practise necessary to begin writing WDM device drivers for Windows XP and Windows 2000. Using these course notes you would be able to develop an immediately useful knowledge of how to write device drivers that would interface hardware to Operating System and to Application Programs.