The heroic story of the invention of antidepressants is a key part of the psychopharmaceutical turn. On Trial revolves around one of its pioneers, psychiatrist Roland Kuhn, who practiced in Münsterlingen, a state-run psychiatric hospital in Switzerland. Kuhn became famous for the 'discovery' of the first antidepressant, Tofranil, and more recently notorious for his numerous trials on often unsuspecting patients.

Largely based on the extensive and previously inaccessible sources of Kuhn's private archive, the book delves into the early days of industry-sponsored clinical research in psychiatry. It examines how the clinic, patients, doctors, nursing staff, corporations, and authorities interacted in the trials.

Conducted from the 1940s to 1980s, the Münsterlingen drug trials are historicised and situated in the period's evolving landscape of experimentation.