Nothing wrecks Captain Eva Innocente's vacation plans quite like an anonymous threat to vaporize billions of people. Hundreds of monoliths have suddenly, materialized in space, broadcasting the same looped message, surrender or be, exterminated. Is the universe being epically, spammed? Surrender to whom? Exterminated when? And how is Eva, commander of a beat-up cargo ship, supposed to prevent it? As panic spreads, a mystery message sends Eva to find...

The Ghost Brigades are the Special Forces of the Colonial Defense Forces, elite troops created from the DNA of the dead and turned into the perfect soldiers for the CDF's toughest operations. They're young, they're fast and strong, and they're totally without normal human qualms.
The universe is a dangerous place for humanity—and it's about to become far more dangerous. Three races that humans have clashed with before have allied to halt

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When Captain Jim Holden's ice miner stumbles across a derelict, abandoned ship, he uncovers a secret that threatens to throw the entire system into war. Attacked by a stealth ship belonging to the Mars fleet, Holden must find a way to uncover the motives behind the attack, stop a war and find the truth behind a vast conspiracy that threatens the entire human race.

Kay and Doc Wink need to find a way to stop the plague that are killing many, is it a work of natural or worst?

One hundred years before Ender's Game, the aliens arrived on Earth with fire and death. Earth Afire by Orson Scott Card and Aaron Johnston is the story of the First Formic War.
Victor Delgado beat the alien ship to Earth, but just barely. Not soon enough to convince skeptical governments that there was a threat. They didn't believe that until space stations and ships and colonies went up in sudden flame.
And when that happened,

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When the alien ship screamed through the solar system, it disrupted communications between the far-flung human mining ships and supply stations and between them and Earth. So Earth and Luna were unaware that they had been invaded until the ship pulled into Earth orbit, and began landing terra-forming crews in China. Politics and pride slowed the response on Earth, and on Luna, corporate power struggles seemed more urgent than distant deaths. In this...