Timelike Infinity

"Timelike Infinity" by Stephen Baxter is the second novel in the Xeelee sequence, set in a universe where humanity has experienced both great triumphs and dark, oppressive times under alien occupation. The story centers around a groundbreaking time-travel tunnel, created from exotic matter, which offers a glimpse into possible futures and pasts, as a group of humans attempt to escape their bleak present. Led by Michael Poole, the characters face complex moral and scientific challenges as they navigate the dangers of time travel and their own fanatic pursuits.