Win32 is defined as a 32 bit interface to [Microsoft Windows]. It superceeds Win16. Is the newest (unreleased) 64 bit version Win64 or just .NET? Tk and Tcl use the Win32 [API] to access OS functions and draw on the screen. [[elaborate on how it can be used for many other purposes and how Tcl uses it]] In the Microsoft newsgroups news://news.microsoft.com I [GPS] have noticed several people refer to Win32 as obsolete. Is it really obsolete now? Have they rewritten the core of Windows with [C#]? Should Tk be modified to use the new [API]? [Benny Riefenstahl]: As I understand it, Win32 is still the basis of Windows programming. The new thing is [.NET] (see there for elaboration).