In Alastair Reynolds' "Revelation Space" series, humanity is slowly coming to the uncomfortable realization that they might be the only spacefaring civilization around--or at least the only one that hasn't been violently wiped out. But this wasn't always the case. Who called the galaxy home in eons past, and where did they all go? Humanity might not be ready for the answers...

Revelation Space Book #1 Spoiler danger zone begins at 45:55 and ends at 1:09:58.