This book shines with its very interesting world. The coolest aspect to me was the mathematics-based space travelling (with sometimes somewhat wonky pseudo-mathematics, admittedly). This book only scratched the surface of what there is to know about the world of Neverness. It seems there are 3 more sequels to this book but they've been out of print for a long time so it may be tricky to get my hands on them. I'll still try, though.
Published Feb. 7, 1988 by D.I. Fine.