The U.S. Army, which has only the most rudimentary understanding of operational art, has designed its tanks, especially the M-1 Abrams Main Battle Tank, for tactical utility with little thought for operational mobility.

This is typical of Second Generation War, French-model armies. The U.S. Abrams Main Battle Tank, which is built by General Dynamics, is essentially the latest version of the French Char B Main Battle Tank that was deployed before World War II.

In contrast, German and Soviet tanks were designed to serve a doctrine of operational mobility. Not many years ago a friend of mine was being shown over the German Leopard II tank by a German officer, who kept stressing the tank's wide tracks.

Puzzled, the American finally asked, "What's the big deal about wide tracks?" The German officer replied, "The Pripet marshes!" The Pripet marshes are a huge area of partially forested wetlands in what is now the former Soviet republic of Belarus.

Bruce Gudmundsson's valuable new book, "On Armor," concludes with an especially thoughtful discussion of the future of armor.

Gudmundsson writes, "At the beginning of the story, these two characteristics (operational mobility and combat power) are embodied in very different classes of vehicles. Light armored vehicles (initially armored cars and trucks) had operational mobility while tanks had combat power.

"In the middle of the story, which also coincides with the middle of the twentieth century, the two principle virtues of the armored vehicle are embodied in a single class of vehicle: an all-purpose tank such as the German Panzer III, the Soviet T-34, or the American Sherman.

"It was not long, however, before the two lines began to diverge again. By the end of the twentieth century, it was no longer possible to combine both operational mobility and first-class combat power in a single vehicle."

I am not sure it is no longer possible, and I would probably use the German Panzer IV with the long-barreled 75mm gun rather than the Panzer III as the German example, but Gudmundsson is correct about the divergence. The U.S. Marine Corps' wheeled Light Armored Vehicle was originally conceived as a way to give some Marine units operational mobility at a time when the M-1 Abrams was taking it away from tank battalions.

"On Armor" is a fine book, one that is essential to understand many of the developments in land warfare in the 20th century. Fourth Generation war renders much of the history that and nothing more; in 4G war conflicts, all tanks in effect become Sturmgeschutze.

Operational art is practiced on the mental and moral levels of war as great sweeps of armored formations deep in the enemy's rear become militarily meaningless.

But history remains important as a record of how people thought through the problems of earlier times. On Armor offers that history of armored warfare better than any other book on the subject.

(William S. Lind, expressing his own personal opinion, is director for the Center for Cultural Conservatism for the Free Congress Foundation.)