Part 3 of excerpts from War Made New: Technology, Warfare, and the Course of History, 1500 to Today, by Max Boot.

A British army colonel noted in 1839: "In no profession is the dread of innovation so great as in the army." Successful adaptation to major technological shifts requires overcoming that dread and changing the kinds of people who are rewarded within a military structure. The rise of railroads and steamships in the 19th century elevated the importance of logisticians and engineers—technocrats who were initially looked down upon by traditional army and navy officers. In the Imperial German Navy, engineering officers were sent to a separate school, they wore less gaudy uniforms without the sashes and imperial crowns sported by regular officers, and they were not allowed to dine in the officers' mess. They even had to endure the indignity of having their wives addressed as "women," not "ladies."

Today, the U.S. Air Force faces difficult dilemmas as it figures out how to integrate unmanned aerial vehicles: Should someone controlling a Predator from a trailer thousands of miles away be a certified pilot? Should control time count as "flying" hours? This may seem a picayune matter, but it looms large in a service where the fastest advancement has always gone to fliers. If the Air Force doesn't give greater promotion opportunities to UAV operators, it cannot attract and keep the best people for these jobs, but if it advances them ahead its fighter-jock culture will inevitably change.

This is part of a broader challenge confronting all Information Age militaries: How to make room for those who fight with a computer mouse, not an M-16. Will traditional warriors--men with shaved heads and hard bodies--continue to run things, or will nerds with bad posture and long hair, possibly even women, assume greater prominence? Two Chinese strategists write that "it is likely that a pasty-faced scholar wearing thick eyeglasses is better suited to be a modern soldier than is a strong young lowbrow with bulging biceps," but, even if that is true, reordering any military along those lines presents a far more profound and problematic challenge than questions about which tank or helicopter to buy. As Eliot Cohen writes: "The cultural challenge for military organizations will be to maintain a warrior spirit and the intuitive understanding of war that goes with it, even when their leaders are not, in large part, warriors themselves."

War Made New surveys many instances where militaries had to change or die. Those armed forces that did not successfully integrate the gun, the long-range bomber, precision-guided munitions, or other important innovations experienced the agony of their members dying in great numbers. But War Made New also looks at some instances of militaries too eager to change in the wrong way. In the 1930s, the U.S. Army Air Corps and the Royal Air Force placed too much faith in the ability of unescorted bombers to win a future war—a doctrinal mistake that cost the lives of tens of thousands of air crews over Europe. In the 1940s Hitler poured vast resources into the development of the V-1 and V-2 that might better have been employed on his conventional forces. And in the 1950s the U.S. Army, Navy, and Air Force did so much to rearrange themselves around the demands of the nuclear battlefield that they were not ready for the actual threat they wound up confronting in the jungles of Vietnam.

There is no rule-of-thumb to suggest how much or how little a military should change in response to technological developments. Each revolution raises painful questions of prioritization such as those that the United States and other countries confront today: Should they pay for more traditional infantrymen and tanks, or push resources into "transformational" programs like surveillance satellites, wireless broadband networks, and directed-energy weapons? Each path has major risks and trade-offs: Paying for larger standing forces can make it easier to respond to today's threats; cutting force strength and using the savings to pay for high-tech hardware can make it easier to respond to tomorrow's threats.

History indicates that the wisest course is to feel one's way along with careful study, radical experimentation, and free-wheeling war games. Paradoxically, revolutionary transformation often can be achieved in evolutionary increments. The Germans did not shift over their entire army to panzer divisions in the interwar years. In 1939-40 only about 10% of German forces were composed of armored units, and the Wehrmacht had more ponies than panzers, but this was enough to produce breakthroughs from Poland to France.

A corollary is that a military revolution does not necessarily sweep aside all old weapons and old ways of doing things. Battleships may have been dethroned as queen of the seas in 1941 but they continued to perform a valuable auxiliary role as a shore bombardment platform into the 1980s. Sweden's King Gustavus Adolphus (1594-1632) did not simply toss out pikes in order to make way for muskets and cannons; he used a combination of weapons, old and new, to achieve maximum effect. Indeed, bayonets continue to be fixed onto rifles (though rarely used) hundreds of years after edged weapons lost their primacy on the battlefield.

This offers a counterpoint to skeptics who deny the existence of an Information Revolution simply because not everything has changed: It never does. On the other hand, this also offers a cautionary lesson that some modern-day J.F.C. Fullers or Billy Mitchells anxious to scrap the tank, the aircraft carrier, and the manned airplane should keep in mind: Introducing "transformational" systems does not necessarily mean getting rid of all "legacy" platforms. Rather, it means readjusting the balance between the two.

"You need to think about how to make a transition," counsels Andrew Marshall of the Pentagon's Office of Net Assessment, "not about how to eliminate current weapons."

Next: Why Military Power--Not Just Economic Power--Still Matters.