Until 1934 the hidden valley of the Nanda Devi Sanctuary, on the border between India and Tibet, had never been entered by human beings. Surrounded by 20,000-foot peaks, which effectively seal off Mt Nanda Devi at their centre, it remains virtually impenetrable even today. Many early explorers, drawn there by the idea of a ‘lost Eden’ in the Himalaya, could only gaze with longing at the Sanctuary – until the ‘terrible-twins’ of pre-Second World War mountaineering, Eric Shipton and Bill Tillman, solved the problem by forcing an entrance up a precipitous river gorge. Subsequent expeditions were beset by tragedy and concern that the fragile ecology of the Sanctuary might be damaged; until, for curious reasons involving the CIA - which the first edition of this book revealed- the Indian government finally decided to ban all visitors. The Sanctuary was briefly reopened  in 2000 for a special millennium expedition, of which Hugh Thomson was a part. Thomson weaves the story of this last journey to the Sanctuary together with those who have gone before him, and gives a tantalizing account of a place described by explorers as ‘more inaccessible than the North Pole'.