Before Failsafe (en Inglés) - Mich Solo

When humanity faces extinction, the heroes embark on an impossible mission to seek help from an alien intelligence 3,500 light years away.

What they discover forces them on a fast-paced journey through history's critical junctures - not to change the past, but to explore what it means to be human.

This isn't your typical time travel story. There are no heroic victories or neat solutions waiting at the end.

Instead, ordinary people must grapple with impossible moral choices while confronting forces that view humanity itself as a problem to be solved. Every act of compassion, every moment of beautiful human chaos, becomes part of a larger argument about whether our species manages to survive.

What sets this story apart is its unflinching examination of humanity's supposed flaws - our irrationality, our inefficiency, our stubborn refusal to be optimized. The crew must navigate not just the dangers of the past, but the temptation to become something other than human in order to save humanity itself.

A philosophical thriller wrapped in hard science fiction, exploring whether the very qualities that make us human are worth preserving - or if survival demands we abandon them entirely.