Improvised Explosive Devices (IED) became the signature threat of both the Afghan and Iraq wars. In Afghanistan they have been responsible for around 50 percent of all ISAF coalition troops killed in combat. Ironically, the concept, as well as the processing instructions to manufacture the deadly devices were provided to the insurgents by the US military themselves in the first place.
The US Army Technical Manual, TM 31-210 reads like a sales pitch to insurgent wannabes on the potentiality, scope and benefits of the device. Quoting from the Introduction:
In Unconventional Warfare operations it may be impossible or unwise to use conventional military munitions as tools in the conduct of certain missions. It may be necessary instead to fabricate the required munitions from locally available or unassuming materials. The purpose of this manual is to increase the potential of Special Forces and guerrilla troops by describing in detail the manufacture of munitions from seemingly innocuous locally available materials. Manufactured, precision devices almost always will be more effective, more reliable, and easier to use than improvised ones, but shelf items will just not be available for certain operations for security or logistical reasons. Therefore the operator will have to rely on materials he can buy in a drug or paint store, find in a junk pile, or scrounge from military stocks. Also, many of the ingredients and materials used in fabricating homemade items are so commonplace or innocuous they can be carried without arousing suspicion. The completed item itself often is more easily concealed or camouflaged. In addition, the field expedient item can be tailored for the intended target, thereby providing an advantage over the standard item in flexibility and versatility.(...)These items were found to be effective in most environments.
IEDs can take the form of suicide bombs, such as Personal-Borne IEDs (PB-IED), Radio-Controlled IEDs (RC-IEDs), Vehicle-Borne IEDs (VB-IEDs), Suicide Vehicle Borne IEDs (SV-IED), Command-Wire IEDs (CW-IEDs), Victim-Operated IEDs (VO-IEDs), and Pressure-Plate IEDs (PP-IEDs).
First used at a large scale in the Iraq war, IEDs soon became a favorite insurgent weapon in Iraq and Afghanistan causing dread, havoc and panic amongst US and coalition forces. IEDs became the object of a momentous cat-and-mouse game between innovative insurgents, continuously tinkering with their artifacts to improve detection avoidance and enhance harming potential, while the U.S. kept trying to counter the problem by throwing billions of US dollars thereupon, in an attempt to concoct adequate armor for military vehicles, efficient sensing devices for early detection, and other defense paraphernalia. IEDs toiled the ground for such swindlers as the suppliers of the infamous fake bomb detector ADE 651, who sold their dowsing rod to 20 countries in the Middle East and Far East, including Iraq and Afghanistan, for as much as USD 60,000 each. The Iraqi government is said to have spent USD 85 million on the devices.
Source: The US Army Technical Manual, TM 31-210 [The Improvised Munitions Handbook (Improvised Explosive Devices or IEDs), Department of the Army, 1969 - original publication; 2007 - electronic edition.]