The term torture refers to acts which inflict severe pain or mutilation on prisoners. Governments, armies and tyrants have inflicted torture on opponents throughout recorded history, chiefly against slaves and rebels, but also against political or religious dissidents.
In the West, the best known cases of torture were inflicted by ecclesiastical and political authorities during the Middle Ages. A well-known example from historical fiction occurs in Ivanhoe, and well-known examples from real history can be found in the Malleus Maleficarum, a manual for witch hunters. Opposition to torture on human rights grounds began in the 20th century, yet torture persists in countries as diverse as China and Sudan.
In a raid on an al-Qaeda safe house in Iraq, U.S. military officials recovered an assortment of crude drawings depicting torture methods like "blowtorch to the skin" and "eye removal." Along with the images soldiers seized various torture implements, such as meat cleavers, whips, and wire cutters. The images, declassified by the Department of Defense, also include a picture of a ramshackle Baghdad safe house described as an "al-Qaeda torture chamber." It was there, during an April 24, 2007 raid, that soldiers found a man suspended from the ceiling by a chain. According to the military, he had been abducted from his job and was being beaten daily by his captors. Earlier Coalition Forces freed five Iraqis who were found in a padlocked room in Karmah. The group, which included a boy, were reportedly beaten with chains, cables, and hoses.
The UN Convention against Torture and Other Cruel, Inhuman or Degrading Treatment defines torture as:
"...any act by which severe pain or suffering, whether physical or mental, is intentionally inflicted on a person for such purposes as obtaining from him or a third person information or a confession, punishing him for an act he or a third person has committed or is suspected of having committed, or intimidating or coercing him or a third person, or for any reason based on discrimination of any kind, when such pain or suffering is inflicted by or at the instigation of or with the consent or acquiescence of a public official or other person acting in an official capacity. It does not include pain or suffering arising only from, inherent in or incidental to lawful sanctions." 
Torture is widely practiced in many countries throughout the world as a means of intimidating the ruling regime's opponents. Amnesty International in Asia & the Pacific states that incidences of torture or ill treatment by the police have been reported in over 140 different countries since 1997.  By far most commonly reported method of torture is physical beatings - other commonly reported methods include:
- Mock execution or threat of death
- Prolonged solitary confinement
It is a matter of dispute whether it serves any valid purpose to distinguish between degrees or levels of torture. To some opponents, "torture is torture" and should always be prohibited. The US maintains that its coercive interrogation techniques are not "torture". While this position has met with considerable resistance from legal experts nationwide, former President George W. Bush vetoed the McCain Amendment, which was intended to tighten the definition of torture. Ironically, under the current administration's definition of "torture", the abuse Senator McCain received while a POW in Vietnam would not be considered torture.
In addition to disagreement over the nature of what is or is not considered torture, controversy exists as to whether torture generally elicits useful information. A large amount of prisoners tortured will eventually break and give up information or confession just to end the torture. John McCain, who is considered both a patriot and a conservative, had his will broken after weeks of torture and the pain of improperly treated injuries, and subsequently signed a written confession stating "I am a black criminal and I have performed the deeds of an air pirate. I almost died and the Vietnamese people saved my life, thanks to the doctors." Examples like this illustrate that rather than evoking truthful statements or valuable intelligence, torture has the equal potential to elicit misinformation, and is therefore of questionable value.
The signatories to the Geneva Convention  in 1949 defined relative classes of persons who may be considered "prisoners". The Bush administration has classified terrorists as unlawful combatants not associated with any signatory power and maintain that previous international conventions have not addressed this classification.
- The Malleus Maleficarum
- Torture, Al-Qaeda Style Drawings, tools seized from Iraq safe house in U.S. military raid, May 24, 2007.
- Mind the Gap: Purpose, Pain, and the Difference between Torture and Inhuman Treatment by Christian M. De Vos