Jonathan Franzen's Purity is a grand story of youthful idealism, extreme fidelity, and murder. The author of The Corrections and Freedom has imagined a world of vividly original characters – Californians and East Germans, good parents and bad parents, journalists and leakers – and he follows their intertwining paths through landscapes as contemporary as the omnipresent Internet and as ancient as the war between the sexes. Purity is the most daring and penetrating book yet by one of the major writers of our time.