From brutal civil wars in Africa to vicious drug-cartel rivalries in Mexico, violence around the world has one thing in common: vast quantities of hand-held weapons such as Kalashnikov assault rifles, mortars and rocket-propelled grenades. Nearly a billion small arms are scattered across the globe, about three-quarters of them in civilian hands. Many have been recycled from recent conflicts, such as last year's Libyan civil war; some have come from former Soviet Union stockpiles. While most are used for hunting, sport shooting and personal protection, millions end up in the hands of rebel groups, gangs and criminals. Some experts argue that the growing proliferation of small weapons can exacerbate a potentially violent situation, but others insist the mere presence of weapons does not necessarily promote violence. This summer the U.N. will try to negotiate a treaty governing the global trade in all weapons. Some negotiators want small arms included, but gun-rights groups oppose overly restrictive regulations on the small arms trade.

John Felton is a freelance journalist who has written about international affairs and U.S. foreign policy for nearly 30 years. He covered foreign affairs for the Congressional Quarterly Weekly Report during the 1980s, was deputy foreign editor for National Public Radio in the early 1990s and has been a freelance writer specializing in international topics for the past 15 years. His most recent book, published by CQ Press, is The Contemporary Middle East: A Documentary History. He lives in Stockbridge, Mass.