Company (http://www.microsoft.com/ ) headquartered in the state of Washington, in the business of writing software primarily (not exclusively) for use on Intel hardware. OR, as some of us see it, in the business of marketing software (and, increasingly, hardware and services). As some of us see it.
Most well known for a series of operating systems known as Microsoft Windows and an application suite known as Microsoft Office.
For a discussion of .NET and Tcl (and Perl and Python) from the Microsoft perspective, see this article in Microsoft's Technet: "Taking Advantage of Windows 2000 and the .NET Platform" [L1 ]