This monograph presents a meticulously researched and deeply documented account of the transformation of India–Tibet relations during the critical period from 1947 to 1962. Drawing on newly accessed archival material, diplomatic cables, political correspondence, and reports of Indian officials posted in Tibet, the study reconstructs—year by year—the dramatic erosion of Tibet’s independence and its implications for India’s national security. The work traces the last years of a free Tibet, the invasion and political subjugation of the plateau by the People’s Republic of China, the signing of the 17-Point Agreement, the dilution and eventual withdrawal of India’s long-standing presence in Tibet, and the Panchsheel negotiations that formally ended India’s special position in Lhasa. It highlights inconsistencies in Indian policy, the strategic warnings issued by leaders like Sardar Patel, and the divergent assessments of Indian diplomats, political officers, and military observers on the ground. Through four structured sections, the monograph documents the dismantling of traditional Indo-Tibetan ties, the consolidation of Chinese military infrastructure, the Tibetan resistance, and the slow but certain drift toward the 1962 border conflict. Rich in historical detail and grounded in more than 2,000 pages of archival sources, the study offers a sober reminder of how misread intentions, idealism, and strategic hesitation profoundly reshaped India’s Himalayan frontier. This monograph stands as a significant contribution to understanding the geopolitical origins of the Sino-Indian boundary dispute and underscores the enduring relevance of Tibet in India’s strategic calculus.