Bernard Werber. Empire of Angels

Meet the second part of the cult duology about Thanatonauts.
Pioneers of "postmortem geographical discoveries," Michel Pinson and Raoul Razorbak, meet again to continue their exploration of paradise, but this time from the inside. They will learn the intricacies of angelic craft and navigate the murky celestial hierarchy. But they wouldn't be true Thanatonauts if they stopped there. Where do angels go after fulfilling their destiny? Who controls it all? And what if the answers to these questions lie in other galaxies?