Few novels can have been more misunderstood than Hermann Hesse’s Steppenwolf. The 1960s guru Timothy Leary thought the experiences of its hero, Harry Haller, with the Magic Theatre were drug-induced psychedelic fantasies, though the clean-living Hesse avoided drugs (apart from taking opium as a sedative after a row with his first wife). Others thought the Steppenwolf was a heroic rebel against conventional society, not seeing that in this guise Haller is consumed with self-loathing and self-pity and that his salvation consists in learning not to be a Steppenwolf. Few have properly appreciated the narrative complexity, the multiple perspectives and the open ending that make this novel a key work of modernist fiction.

Steppenwolf reflects a midlife crisis, which, as Gunnar Decker’s biography shows, was long in the making. Hesse carried heavy psychological baggage from his childhood in Württemberg, where he was born in 1877. His parents, devout Lutheran ex-missionaries, had no idea how to handle an unruly teenager who ran away from boarding school and threatened suicide. They alternately urged him to find God and sent him to a mental asylum.

Despite this bad start in life, discussed by Decker with many acute insights, Hesse established himself before the First World War as a successful though rather old-fashioned novelist. By 1920, however, the crisis was at hand. One hardly knows where to begin. His marriage to Maria (‘Mia’) Bernoulli,