Berkeley: University of California Press, 1977. xii+218p., foreword, index, illustrated with plates from photographs, very good first edition in dj.
From dj flap text: "The cowboys' skill with half-wild cattle fascinated the schoolboy. He treasured their accounts of guiding Theodore Roosevelt on big-game hunts and of Herbert Hoover seeking gold - incidents not recorded in the biographies of either man." The "spy" part comes in when "he was lured to Mexico by Madero's revolution. Hoping to write newspaper dispatches more informative than Collier's professional war correspondent, he joined the rebel army. Soon arrested as a spy.."