> i assume he's coordinating the crt versions?  apparently a lot of people use these.

So do I :)  He's definitely got access to the correct compiler versions, so I'm sure he's using them (via distutils/setuptools, which will always try to use the correct one).

> i'm not clear on why gohlke's stuff is necessary, and why pypi/pip/distutils is not adequate

It's not necessarily easy to get exactly the right compiler, and since Python generally relies on old and outdated ones (because 2.7 lives forever and cannot change) people often need multiple versions installed at the same time.

pip+wheel is adequate once library developers publish wheels (or republish Gohlke's wheel of their library). pip+distutils is very fiddly.

> shapely is the only library i've run into that needed gohlke's binaries.  of course, i didn't try to install numpy/scipy manually, the internet said that this is hard on windows, and to just use something like winpython/pythonxy.  are these problems all related to this crt issue?

numpy and scipy are due to requiring a Fortran compiler. The Intel compiler is compatible with MSVC, but does not have a Free(tm) license, while gfortran (gcc) does and is not strictly compatible with MSVC (there are some MinGW forks that are very close though).

So in effect, yes, the fact that the CRT has to match in every pre-built binary is the problem (less of a problem on Linux because nobody ever imagines that the C runtime might be compatible, and so everyone needs a compiler all the time - therefore, compiling is easier than distribution, whereas on Windows distribution is easier than compiling </oversimplification>).