'Happy Valley' was the name given to the region of Kenya's Central Highlands where a community of affluent, hedonistic white expatriates settled between the wars. Including the writer Karen Blixen (Isak Dinesen), the pioneering aviator Beryl Markham and the troubled socialite Idina Sackville whose life was told in Frances Osborne's bestselling The Bolter, the Happy Valley set's notoriety was sealed in 1931 with the sensational - and still unsolved - murder of the Earl of Errol, the investigation of which laid bare the extent of the set's decadence and irresponsibility, and made for another bestselling book in James Fox's White Mischief. But what is left now? Juliet Barnes, who has lived in Kenya for many years, has set out to explore Happy Valley in a remarkable and indefatigable archaeological quest to find the homes and haunts of this extraordinary and vanished set of people - grand residences like Clouds up in the hills that once hosted opulent and scandalous parties. With the help of African guides, and guided by the memories of elderly expats she tracks down to the Muthiaga old enough to have first-hand memories of the likes of Idina and Lord Errol and the lives they led, what she finds - ruins reclaimed by luxuriant bush, tumbledown dwellings in which an African family ekes a subsistence living, or even a modest school - is a revelation of the state of modern Africa that makes the gilded era of the Happy Valley set seem even more fantastic. A book to set alongside such singular evocations of Africa and its strange colonial history as The Africa House, The Ghosts of Happy Valley: The Biography is a mesmerising blend of travel narrative, social history and personal quest.