Where can I find some software that runs on Windows that will show me
not just duplicated files but duplicated or nearly duplicated
DIRECTORIES? I have found many tools that are fine for finding
duplicated files, for comparing directories and synchronizing them but
none for listing identical or very similar directories.

Sorry, that's not what I'm looking for. I already use Beyond Compare
and it's, indeed, beyond compare, for comparing directories and
synchronizing them. BC v3.0 will have a duplicate file finding
capability accoording to the developers but it's not there now, except
at the level of a pair of directories. If you have a lot of similar
directories then finding and eliminating all duplicates is a very
labor intensive process. I an currently using a combination of
utilities, including noclone and beyond compare. If noclone allowed
one to right click on a path and run BC then it would all be much
easier.

Note the subject: finding duplicate directories, not comparing
duplicate directories.

Thanks anyway.