The opening chapter of Benjamín Labatut’s second novel is such a perfect distillation of his technique that it could serve as a manifesto. One morning in 1933, Austrian physicist Paul Ehrenfest pays a visit to his disabled child, Vassily. Ehrenfest has enjoyed a dazzling career, but recently has been seized by despair. Nazism is the most urgent threat, but Ehrenfest is troubled too by a less tangible development: the quantum revolution, most notably the work of Hungarian wunderkind John von Neumann. Ehrenfest experiences this new theoretical direction as a kind of unravelling, a fog of “logical contradictions, uncertainties, and indeterminacies”...