The Turnstone is a vivid and wide-ranging account of more than sixty years of travel, medical research and clinical practice. Geoffrey Dean was born in Wales in 1918 and trained as a doctor in Liverpool before serving with distinction as a medical officer in Bomber Command. After the war he moved to South Africa, where he lived with his family for the next twenty years. During this period Dean studied the epidemiology of porphyria, a disease that can cause paralysis; his book The Porphyrias was first published in 1963. Geoffrey Dean became Director of the Medico-Social Research Board of Ireland in 1968. The author’s research has taken him around the world, and besides his research findings, the book has a rich array of anecdotes and adventures, ranging from the threat of imprisonment in South Africa to a period spent as the personal physician to the multi-millionaire Governor of the Fiji Islands.