When Chicagoan Russell Stone finds himself teaching a Creative Nonfiction class, he encounters a young Algerian woman with a disturbingly luminous presence. Thassadit Amzwar's blissful exuberance both entrances and puzzles the melancholic Russell. How can this refugee from perpetual terror be so happy? Won't someone so open and alive come to serious harm? Wondering how to protect her, Russell researches her war-torn country and skims through popular happiness manuals. Might her condition be hyperthymia? Hypomania? Russell's amateur inquiries lead him to college counselor Candace Weld, who also falls under Thassa's spell. Dubbed Miss Generosity by her classmates, Thassa's joyful personality comes to the attention of the notorious geneticist and advocate for genomic enhancement, Thomas...