which people either love or hate. It's a variant of the "cold numbers" theme -- an ancient alien civilization leaves an asteroid full of small spacecraft that are obviously millions of years old. The ships still work but the navigation system is incomprehensible. It falls on a group of the desperate, the "prospectors," to hop in the ships, dial in a destination and hope that it is within the range of human life support on the ship (it sometimes isn't). They are promised a "share" of whatever discoveries they can make. Lots of 70's sex drugs and psychotherapy as the book is narrated as the (again an antihero) protagonist is having a session with his computerized shrink as he sorts through the issues that made him a very rich person on his last voyage.
Lots of mysteries, Pohl answers ALL of them -- most importantly why an alien civilization would even abandon the ships in the first place. It's just that sometimes you may not like the answers -- it's kind of borderline classic sci-fi. I loved them personally....he wasn't through until the adventure ended up being cosmological in what it dealt with.