Hamilton, Peter F. Salvation sequence.

The comparative utopia of twenty-third century Earth is about to go dreadfully awry when a seemingly benign alien race is abruptly revealed to be one of the worst threats humanity has ever faced. Driven by an intense religious extremism, the Olyix are determined to bring everyone to their version of god as they see it. But they may have met their match in humanity, who are not about to go gently into that good night or spend the rest of their days cowering in hiding. As human ingenuity and determination rises to the challenge, collective humanity has only one goal--to wipe this apparently undefeatable enemy from the face of creation. Even if it means playing a ridiculously long game indeed