One evening in 1924, Katharine "Kay" Swift--the restless but loyal society wife of wealthy banker James Warburg and a serious pianist who longs for recognition--attends a concert. The piece: Rhapsody in Blue. The composer: a brilliant, elusive young musical genius named George Gershwin. Kay is transfixed, helpless to resist the magnetic pull of George's talent, charm, and swagger. Their ten-year love affair, complicated by her conflicted loyalty to...