I can’t find volume four of the Demon Princes series anywhere. I just finished Marune: Alastor 933.
RE your two comments:
GSWarrior
I picked up the Jack Vance Demon Princes omnibus version at a bookstore years ago. I think you can still find it on amazon/ebay. I recently downloaded it from itunes for more convenient reading. I’m thinking of downloading The Dying Earth omnibus at some point soon so I can revisit Cugel, Rhialto, etc.
Tax-chick
Telzey Amberdon is a collected series of short stores, and a novelette about a girl who discovers that she has psi-powers and develops the ability to communicate with and read/alter the minds of others, and potentially other creatures. I think that the whole mental/psi thing was big in the 50’s/60’s, bigger than it is now. Anyway, once she discovers her powers, she is exposed to a world where there are others who have similar powers, many of which are quite dangerous, etc. Adventures ensue.