Greg, Great response. I think we know where we each stand. Please go ahead with a new design. (That's trust, not carte blanche.) Just one thought: the more I think about it, the less I like sys.importers: functionality which is implemented through sys.importers must necessarily be placed either in front of all of sys.path or after it. While this is helpful for "canned" apps that want *everything* to be imported from a fixed archive, I think that for regular Python installations sys.path should remain the point of attack. In particular, installing a new package (e.g. PIL) should affect sys.path, regardless of the way of delivery of the modules (shared libs, .py files, .pyc files, or a zip archive). I'm not too worried about code that inspects sys.path and expects certain invariants; that code is most likely interfering with the import mechanism so should be revisited anyway. On the lone .pyc issue: I'd like to see this disappear when using the filesystem, I see no use for it there if we support .pyc files in zip archives. --Guido van Rossum (home page: http://www.python.org/~guido/)