Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Re: The Mercy Men

This is a fine SF suspense novel focusing on an experimental center which solicits volunteers for experiments.Jeff Meyer believes his father disappeared at the center, and so he joins the Mercy Men (ie the volunteers for research) to find him.The plot has some unexpected twists. The conclusion is a satisfying one.See also Nourse's "Raiders from the Rings."Recommended.