Narendra Modi’s pilgrimage to Tibet heralds a new warmth in Sino-Indian relations, but the emerging superpowers have a long and complex history of contested priorities in the Himalayas. Keay is author of Midnight’s Descendants, a sweeping history of South Asia; Duff’s Sikkim: Requiem for a Himalayan Kingdom tells the remarkable true story of India’s annexation of Sikkim in 1975. It’s a tale of love, intrigue and the Cold War in Asia.