Frederik Pohl - [Heechee 01] Gateway

Gateway opened on all the wealth of the Universe...and on reaches of unimaginable horror.

Wealth ... or death. Those were the choices Gateway offered. Humans had discovered this artificial spaceport, full of working interstellar ships left behind by the mysterious, vanished Heechee. Their destinations are preprogrammed. They are easy to operate, but impossible to control. Some came back with discoveries which made their intrepid pilots rich; others returned with their remains barely identifiable. It was the ultimate game of Russian roulette, but in this resource-starved future there was no shortage of desperate volunteers.

When prospector Bob Broadhead went out to Gateway on the Heechee spacecraft, he decided he would know which was the right mission to make him his fortune. Three missions later, now famous and permanently rich, Robinette Broadhead has to face what happened to him and what he is...in a journey into himself as perilous and even more horrifying than the nightmare trip through the interstellar void that he drove himself to take!