The great Prussian military theorist Carl von Clausewitz, in his classic On War, introduced the idea of friction in war. Friction was one of the most important ideas that Clausewitz put forward. His application of the term is generally taken to be limited to events on the field of battle. But had Clausewitz lived to the end of the 20th century, he undoubtedly would have broadened his understanding of friction to include the nexus between war and policy making. He would have done so because his most fundamental insight, apart from the significance of friction in war, was his insistence upon the priority of policy over war. Cimbala applies the concept of friction to a number of 20th century cases of war and policy making. He also applies it to some plausible scenarios for the next century. Although many U.S. military planners and policy makers appear to place their faith in technology as the sine qua non of success in security and defense policy, technology can be self defeating and myopic if political and strategic vision are lacking. For example, the mindless pursuit of information warfare in all its varieties may convince potential U.S. opponents that infowar is a cost effective way of negating U. S. military power. A provocative analysis for scholars, students, military professionals and other policy makers involved with strategy and military policy issues.