Good fine. I had looked on abebooks, but didn't see that. It seems like a popular series (I really don't know much about it), but like you pointed out, it seems to almost always be sold individually.
I have the hardback 5 volume set of Spivak's A Comprehensive Introduction to Differential Geometry that is in pretty good shape. Is there any value to that set? I tried looking it up, but I don't really see many people selling whole sets, so I can't tell...
Thanks.