THIS BIOGRAPHY MAY be Caroline Moorehead’s best yet. That is not an easy feat, since they have all been excellent: superbly crafted, engaging and engaged. But Martha Gel/horn leaps off the page. Gellhorn’s gift was for the vivid detail which makes a scene or subject come alive: that is Moorehead’s gift too, together with a cool and humorous detachment, which the two also share. When Martha arrived in Paris in 1930, Moorehead writes, ‘Parisian ladies were wearing Fauvist orange, yellow and shocking pink. On their heads perched vegetables, and they carried handbags shaped like telephones . . . It was all a long way from Madrid.’ That too, amid the agonies of the Civil “War, Moorehead captures in a few sharp details: people still watering their plants in the few buildings that continued to stand; the blood stained sheets in Martha’s hotel being ironed and put back on the beds.