This work investigates the geopolitical motivations and logistical realities behind the 1904 British military expedition into Tibet led by Colonel Francis Younghusband. Peter Fleming, a noted travel writer and historian, utilizes primary source documents and contemporary accounts to reconstruct the mission's progression. He examines the tension between British imperial interests in India and the isolationist policies of the Tibetan government, arguing that the invasion was a product of both genuine strategic anxiety and personal ambition. The narrative framework provides a detailed chronological account of the march from Sikkim to Lhasa.

Historians frequently cite this work for its accessible prose and its ability to synthesize complex imperial politics into a coherent narrative. Experts note that while the book reflects the perspective of its era, it remains a foundational text for understanding the specific military and diplomatic maneuvers of the Younghusband mission.