Hi Mark,

"...There appear to be far more 'User-added Datasets' than there are
TDF files in my GUIDE8 directory -- is this because many live on CD-ROM
only?"

Nope. It's because one TDF file can describe multiple datasets. If
you look at, for example, 'cd_data.tdf', you'll see that it describes
the quasar, BL Lacertae, active galactic nuclei, etc. datasets...
eleven datasets in that file. I just found it simpler to manage things
that way.

-- Bill