Is madness the price we pay for consciousness? And how much has our comprehension moved on since the 19th century, when psychiatry was in its infancy and “lunatics” were locked away in prison-like asylums?

Those are the questions posed by Sebastian Faulks’ novel Human Traces, which charts how two men seek to unravel “the metaphysical enigma” of the mind over a 50-year period between the 1870s and the 1920s.