I'm trying to build an extension (Imaging) which depends on a number of external libraries (JPEG, Zlib, Tk). Rather than hard code the locations of the libraries in the setup.py, I set my INCLUDE and LIB environment variables so that MSVC picks up the libraries automatically. Unfortunately, this doesn't seem to work properly, as distutils ignores these variables! Checking in the source, I see that this is deliberate (see get_msvc_paths and set_path_env_var in msvccompiler.py). I don't believe that this decision is correct - it leaves the user no way, short of modifying the registry manually, to add include/library directories to the standard paths. So manually hacking setup.py becomes a necessity. Can I suggest that msvccompiler.py *adds* the current entries to INCLUDE and LIB, rather than replacing those variables completely. Or at least, that another way of including include/library directories external to setup.py be available... Thanks, Paul.