The British Expeditionary Force at the start of World War I was tiny by the standards of the other belligerent powers. Yet, when deployed to France in 1914, it prevailed against the German army because of its professionalism and tactical skill, strengths developed through hard lessons learned a dozen years earlier. In October 1899, the British went to war against the South African Boer republics of Transvaal and Orange Free State, expecting little resistance. A string of early defeats in the Boer War shook the military s confidence. Historian Spencer Jones focuses on this bitter combat...