War is an organized, armed, and often a prolonged conflict that is carried on between states, nations, or other parties typified by extreme aggression, social disruption, and usually high mortality. War should be understood as an actual, intentional and widespread armed conflict between political communities, and therefore is defined as a form of political violence. The set of techniques used by a group to carry out war is known as warfare. An absence of war (and other violence) is usually called peace.

In 2003, Nobel Laureate Richard E. Smalley identified war as the sixth (of ten) biggest problems facing the society of mankind for the next fifty years. In the 1832 treatise On War, Prussian military general and theoretician Carl von Clausewitz defined war as follows: "War is thus an act of force to compel our enemy to do our will."

While some scholars see warfare as an inescapable and integral aspect of human culture, others argue that it is only inevitable under certain socio-cultural or ecological circumstances. Some scholars argue that the practice of war is not linked to any single type of political organization or society. Rather, as discussed by John Keegan in his History of Warfare, war is a universal phenomenon whose form and scope is defined by the society that wages it. Another argument suggests that since there are human societies in which warfare does not exist, humans may not be naturally disposed for warfare, which emerges under particular circumstances. The ever changing technologies and potentials of war extend along a historical continuum. At the one end lies the endemic warfare of the Paleolithic^{[citation needed]} with its stones and clubs, and the naturally limited loss of life associated with the use of such weapons. Found at the other end of this continuum is nuclear warfare, along with the recently developed possible outcome of its use, namely the potential risk of the complete extinction of the human species.

Ishmael Beah (born on November 23, 1980)) is a former Sierra Leonean child soldier and the author of the published memoir, A Long Way Gone: Memoirs of a Boy Soldier.

In 1991 a vicious civil war overtook Sierra Leone, the country in which he was living. The rebels invaded Beah's hometown, Mogbwemo, located in the Southern Province of Sierra Leone, and he was forced to flee. Separated from his family, he spent months wandering south with a group of other boys. At the age of 13, he was forced to become a child soldier. According to Beah's account, he fought for almost three years before being rescued by UNICEF. Beah fought for the government army against the rebels. In 1997, he fled Freetown by the help of the UNICEF due to the increasing violence and found his way to New York City, where he lived with Laura Simms, his foster mother. In New York City, Beah attended the United Nations International School. After high school, he enrolled at Oberlin College and graduated in 2004 with a degree in Political Science.