Geoff Chappell - Software Analyst
The overwhelming bulk of the standard Win32 shell is implemented in SHELL32.DLL in all versions of Windows, even of the Windows that ran from DOS. Indeed, SHELL32 is so far and away the main shell component that for most practical purposes it is the shell.
SHELL32 also shipped with Internet Explorer, in versions 4.0 and 4.01, which gave the option of installing a so-called integrated shell. This was arguably a device by Microsoft to encourage adoption of Internet Explorer by leveraging the natural inclination of Windows users to have today some improvements to Windows that they would otherwise have to wait for (and pay for).