A (Miles) Gemini is a stylish, twin-engine, four-seater wooden airplane; Joburg is Johannesburg; and this quirky, engaging narrative relives a 1947 flight from England to South Africa, a picturesque 6,000-mile pleasure trip that was also a doomed missionary journey. Lewis (b. 1898) has had a long and lively career: a pilot in both World Wars, a flying instructor in China, one of the founders of the B.B.C., a television executive, and the author of at least one minor classic, Sagittarius Rising (1936). But he was also, improbably enough, a devoted disciple of Gurdjieff, and the official purpose for going to ""Joburg"" was to reconnoiter a site for a refugee colony of the Master's followers, who were anticipating an imminent cataclysm in the Old World. Lewis, his wife Olga, and others eventually managed to establish the colony, called Donkerhoek, on the High Veld; but it soon foundered, not least because, to everyone's surprise Gurdjieff was discovered to be alive (though not well) and living in Paris. It was too early for the Diaspora to begin. At any rate, the flight was a lovely one, proceeding in sometimes leisurely, sometimes tricky and heart-pounding, jumps from Reading to Paris to Nice to Milan to Athens to Tobruk to Cairo to Wadi Halfa (Sudan) to Khartoum to Juba to Nairobi to Kasama to Salisbury to Johannesburg. Lewis has something of Saint-Exupâ€šry's lyrical vision, his love of the natural world beneath his wings, his sense of the pilot as a highly vulnerable demigod--a feeling sharpened by the fact that the Lewises were flying practically without instruments and, in Africa, with the sketchiest of maps. Lewis is given to eccentric, religio-scientific musings, â€¦ la Immanuel Velikovsky and Hans Hoerbringer, but his hearty joie de vivre, warmly nostalgic but never sentimental, keeps him right on course. An unusual, rewarding memoir.