I got Neverness used from Amazon, it didn't cost too much and came right away, so I guess I got lucky!
The other three books in the series are still in print in England! I ordered those from Amazon, too, they took forever to get over the ocean, but those three books are completely awesome!!! Neverness is the intro to the following three books...
Neverness is a bit hard to get into right at the beginning...hang with it and you will be well rewarded. There is a whole thread dedicated to this over at the Hangar, so if you get discouraged, please pop over there and read the thread in the Zindell forum. And the rest of the series (well, to be honest, I've only finished two of the three books) ARE ABSOLUTE BUTT KICKERS!!
Danlo is just a wonderful character!
I just finished the middle book of the three Danlo books, called The Wild and it blew me away.

If you like philosophy and theology mixed in with your science fiction, you will probably love Zindell.
