A man chosen to explore space for humanity is sent on a dangerous mission outside of known space to seek an unknown enemy.

This was probably one of the first big, serious, complex SF novels that I read. I was too young, not yet an adult, though it felt like it. I was disappointed by the first book in this SF trilogy, not realizing it was a trilogy. If I could find it again (called Emprise), I think I would enjoy it better now. The rest of the books were more to my liking.