It wouldn't make much sense to publish a data-centric application to the Web without providing some kind of authentication. The best option with Windows Azure is Forms authentication. Since Microsoft recently released Active Directory for Windows Azure, you can also use Windows authentication. However, in this context we can't simulate a departmental environment, so entering a user name and password is a good choice anyway. Part 2 of this series showed you how to implement Forms authentication and user management. Follow the steps described in Part 2 to implement Forms authentication, including the addition of the Silverlight desktop client.