The .NET Framework provides a set of classes in the System.IO namespace to allow synchronous and asynchronous reading from and writing to data streams and files which are very much required in our real life applications to read, write, or manipulate files and directories.  .NET Framework 2.0 has introduced a new set of classes in the Framework Class Library (FCL) that allow us to work with the NTFS Access Control Lists.  We can get object owners, security descriptors, create security descriptors, and much more.  All of this resides under the System.Security.AccessControl namespace.  The sample code snippets in this article have been written in C#.