The importance to an enemy's intelligence services of information regarding such targets vital to the United States as important installations, plant locations and shipping routes is generally recognized. Although the methods for withholding such information from the enemy are not foolproof, they are at least clear and unclouded by conflicting values. What is not so generally recognized is the importance, in connection with an enemy's plans for the destruction of targets, of detailed economic data. One of the few writers in this field expresses it this way:
The targets which you are after constitute, in essence, the vulnerable areas of the enemy's way of making war and maintaining a functioning society; and these most vulnerable areas cannot be picked out from the least (or less) vulnerable areas until a great deal is known about the enemy's entire way of life and his entire way of making war…. Before the planes went off on their first mission of systematic destruction, the planners for the bombardment of Germany had to know a very great deal about the airframe, aircraftengine and aircraft-component production, the production of ball bearings, of synthetic rubber, and of oil. Moreover, before they decided that these sectors of the economy were the ones whose destruction would give them the most significant, rapid and permanent weakening of German war-making capacity, they had to know a very great deal about other sectors.