Scholars of ancient China and students of military strategy have devoted considerable attention to Sun Tzu's The Art of War. Intelligence experts, in contrast, occasionally cite his chapter on 'The Use of Spies' but do not seem to engage his text. Part of the problem is the difficulty of translating his oracular adages; Western experts in Chinese history rarely understand the arcana of espionage, while intelligence scholars usually know no Chinese. Sun Tzu amply repays an effort to study his text, however, as he presents one of the oldest extant descriptions of an intelligence system - one that is, moreover, still insightful in our modern age.