What do you do if your son, who has grown up with privileges you have enabled, behaves in a way that threatens not only his own wellbeing but also that of your family? This question lurks behind Frederic Spotts’s febrile, compulsive account of the career of Thomas Mann’s talented, wayward and depressive eldest son, Klaus, the author of numerous novels, essays, lectures and plays during the period when Nazism stalked Europe. Spotts subscribes to a fashionable thesis that the way Thomas Mann brought him up was a prime cause of his son’s demise, aged forty-two, in the aftermath of the Second World War. Klaus’s fatal overdose, whether accidental or intended, stemmed from a Todessehnsucht that may be ascribed to genes – Thomas’s sisters both took their own lives – or to a variant strain of the German Romantic disease. It is also the type of finale pathétique that the author of a biographical novel about Tchaikovsky had long been honing.

Klaus and his elder sister, Erika, were sometimes taken as twins, though they were born a year apart. In youth they could have been models for Cocteau’s Les Enfants Terribles (Klaus in fact later adapted his French exemplar’s drug-driven novel for the theatre). They revelled in pranks as children, amateur