Chapter One

Knowledge of the Enemy
Strategic Intelligence

"No war can be conducted successfully without early and good intelligence,” wrote the great Duke of Marlborough. George Washington agreed: “The necessity of procuring good intelligence is apparent and need not be further argued.” No sensible soldier or sailor or airman does argue. From the earliest times, military leaders have always sought information of the enemy, his strengths, his weaknesses, his intentions, his dispositions. Alexander the Great, presiding at the Macedonian court as a boy while his father, Philip, was absent on campaign, was remembered by visitors from the lands he would later conquer for his persistence in questioning them about the size of the population of their territory, the productiveness of the soil, the course of the routes and rivers that crossed it, the location of its towns, harbours and strong places, the identity of the important men. The young Alexander was assembling what today would be called economic, regional or strategic intelligence, and the knowledge he accumulated served him well when he began his invasion of the Persian empire, enormous in extent and widely diverse in composition. Alexander triumphed because he brought to his battlefields a ferocious fighting force of tribal warriors personally devoted to the Macedonian monarchy; but he also picked the Persian empire to pieces, attacking at its weak points and exploiting its internal divisions.

The strategy of divide and conquer, usually based on regional intelligence, underlay many of the greatest exploits of empire building. Not all; the Mongols preferred terror, counting on the word of their approach to d