Do you need to connect your Linux Desktops or Servers to Microsoft's Active Directory (AD)? If you do, now you can learn how to do it straight from the source at Microsoft's TechNet site in the article: Authenticate Linux Clients with Active Directory.
Do you wonder why you'd want to do this? It may not be intuitively obvious but there are IT shops out there (maybe even yours) that use Windows exclusively because of Active Directory authentication. Linux is, or was, often excluded because of its inability to integrate successfully with AD. There are a few products like LikeWise Software's Active Directory product and Quest Software's One Identity Solution that provide commercial solutions for Active Directory integration.
The TechNet article only uses free software for the solution which is kind of shocking considering that it is a Microsoft article. So far Microsoft doesn't supply any Linux software so they have to use what's freely available like the rest of us.
One note about AD integration products and AD integration in general is that once you've connected your Linux machine to an AD domain, you may be in "for life" because I've had a great deal of trouble totally removing my Linux systems from AD. It seems to really mess up the works, so to speak, and from my experience--it's easier to install than unstall, so proceed with caution.