I think it would be helpful if the Python documentation included certain high-level information about multi-threading in Python.

At minimum, I think it would help for the documentation to provide a definition that can be linked to of what it means when some part of the Python documentation says something is "thread-safe".  In particular, such a definition could clarify that this is different from being atomic.  This might best be addressed by an entry in the glossary for the term "thread-safe".
  
Other documentation possibilities include stating what guarantees one should or should not expect regarding thread-safety, both within and across implementations, and providing centralized guidance on how to approach multi-threaded programming in Python.  A HOWTO is one possibility for addressing these other possibilities.

This issue stems from the discussion in issue 15329, which is more specific.

This sounds like a good idea. Either a HOWTO or a FAQ would sound appropriate.

If no one gets to it first, I'll write-up a draft when I get a chance.

Given the scope of the issue, a concurrent programming howto that lists some of the available options and the caveats associated with each of them seems worthwhile.