'If you don't go after the network, you're never going to stop these guys. Never.'

Underbelly or "deep buried" IEDs continued to take an even greater toll -- more than half of all coalition forces killed early this summer, for example, although only 15 percent of all bombs were classified as deep buried. The Pentagon agreed to buy at least 7,800 sturdy Mine Resistant Ambush Protected (MRAP) vehicles with V-shaped hulls for approximately $1 million each. Prudent soldiers on patrol now searched every road culvert; some units began welding shut manhole covers.

An incident on June 28 in the East Rashid neighborhood of Baghdad illuminated a disquieting trend: A single underbelly IED, so violent that investigators initially believed the blast came from several car bombs, killed five soldiers and wounded seven.

Bombmakers increasingly used homemade explosives brewed from fertilizer-based urea nitrate in kiddie swimming pools or huge aluminum cauldrons, then spread on flat rooftops to dry and packed in rice bags. On July 17, bombers detonated 1,500 pounds of homemade explosives in a culvert north of Baghdad. The blast heaved a 26-ton armored vehicle 60 feet through the air, killing two Navy crewmen, according to investigative documents. Other bombmakers in late 2006 began using acetone to leach the explosives from artillery and mortar shells; much lighter and more portable, the stuff could then be molded into car wheel wells or hidden almost anywhere.

Multiple suicide truck bombs were orchestrated to penetrate sturdy perimeter defenses, like the twin blasts in late April of this year that killed nine soldiers from the 82nd Airborne in a schoolhouse command post north of Baghdad.

Another nasty variation first appeared in October 2006 with the first use of chlorine gas in an IED. Sixteen more chlorine attacks would occur, but insurgents found, as World War I soldiers had, that "it is very difficult to create a lethal concentration of chlorine gas," an Army colonel in Baghdad reported. "The gas cloud rapidly dissipates."

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Defeat the device. Train the force. Attack the network.

Meigs, a retired four-star Army general, had repeated those three phrases a thousand times since becoming JIEDDO director in December 2005.

In the early years of the Iraq war, the U.S. government's counter-IED efforts had focused overwhelmingly on defeating the device, and more than half of Meigs's budget still went to preventing detonation and, if that failed, mitigating the blast. In fiscal 2007, for example, $113 million would be spent on mine rollers, a World War II technology using heavy cylinders to trip pressure plate triggers in front of a convoy.

The "molecular sniffer" long coveted by U.S. Central Command arrived on the battlefield in the guise of Fido, a $25,000 machine developed by an Oklahoma company as part of a Pentagon program called Dog's Nose. Modern explosives have very low vapor pressures, and therefore emit few molecules for a sniffer to detect; but Fido's sensor -- heated above 200 degrees Fahrenheit -- was effective enough that hundreds were deployed, including more than 70 mounted on mobile robots. "This is the closest thing we can get to a dog," a government engineer said.

Some technologies thrived: Warrior Alpha drones; surveillance cameras on towers and blimps; ground penetrating radar mounted on a South African-built Husky vehicle to detect buried IEDs. In trying to "pre-det" -- prematurely detonate -- bombs with radio signals, EA-6B Prowler electronic warfare planes flew above roads in Iraq and Afghanistan. The missions were called "burning the route."

Other technologies flopped. Forerunner, an unmanned vehicle carrying counter-IED gear, was to be "tele-operated" with remote controls by soldiers in a trailing vehicle. It "simply did not work" and was banished from the theater, according to a JIEDDO document. The controls proved sluggish, and some operators developed motion sickness while trying to drive Forerunner via a television monitor in the jouncing trail Humvee.