In 2016, the Noordbrabants Museum in the Dutch city of Den Bosch held a special exhibition devoted to the work of Hieronymus Bosch, who died 500 years ago. This late-medieval artist lived his entire life in the city, and caused an uproar with his fantastical, violent, and utterly unique paintings detailing the pleasures and pains of heaven and hell. In preparation for the exhibition, a team of Dutch art historians crisscrossed the globe to unravel the secrets of his art. They used special infrared cameras to examine the sketches beneath the paint, in the hope of discovering more about the artist’s intentions. They also sought to establish which of the paintings could be attributed to Bosch himself, and which to his pupils or followers. The experts shuttled between Den Bosch, Madrid and Venice, cutting their way through the art world’s tangle of red tape, resulting in the controversial and extraordinary discovery of a lost Bosch painting.