In January 1947, a chance discovery rocked the world of natural science -- over 3,000 rare and precious specimens of butterflies had vanished from Australia's most prestigious museums in Sydney, Melbourne, and Adelaide. Alarmingly, the missing insects included many priceless 'holotypes' -- the first specimen of a given species to be identified, against which all others are compared. On the other side of the world, New Scotland Yard descended on a country house in Surrey, where they found a trove of over 40,000 butterfly specimens. The culprit was Colin Wyatt, a Cambridge-educated ski champion, mountaineer, wartime camouflager, artist, and amateur naturalist whose high-flying exploits cut a path from the Alps of Europe to a London court room to a final expedition to the jungles of Guatemala. Drawing on unpublished case files, dossiers, and private archives, The Butterfly Thief pieces together Wyatt's enigmatic life story and his decades-long impact on the world of natural history.