INTRODUCTION In recent years, the global proliferation of conventional weapons has earned a prominent, if not a central, place on the increasingly crowded post-Cold War international security agenda. But while public, academic, and governmental awareness of the problems associated with the proliferation of conventional weapons is growing, the diffusion of light weapons (a subset of conventional armaments) remains seriously under-examined. This is somewhat surprising given that ninety per cent of all deaths and injuries sustained in the course of intrastate conflicts since 1993 were the result of direct fire from light weapons.(f.1) For those interested in dealing with the weapons that kill people in armed conflict, it is also disturbing; for, as one recent study concludes, 'before efforts to limit light weapons are likely to be effective, the issue itself must receive significantly more national and international attention.'(f.2) Simply stated, unless and until the ubiquity, ready availability, and continuing proliferation of light weapons is recognized as a serious impediment to democratization, development, good governance, and peacebuilding, it is unlikely that serious steps will be taken to develop a comprehensive strategy for dealing with them. The purpose of this article is threefold: to provide an overview of the causes and consequences of the ready availability and continuing proliferation of light weapons; to develop a framework for thinking about practical, realistic, and constructive measures to address the problem; and to identify ways in which Canada might take the lead in advancing this agenda. After a discussion of the nature of light weapons, the article develops four propositions: 1 the ready availability and continuing proliferation of light weapons pose serious challenges to development, democratization, good governance, and other aspects of 'sustainable human security'; 2 underpinning the diffusion of light weapons is a complex ecology of causation that includes the failure of states to provide adequate security against threats of organized or unstructured violence, the persistence of militarized cultural forms, the increased availability of light weapons on the international market, and the absence of any generally agreed international norm limiting the rights of states to acquire such weapons; 3 to be effective, political measures will have to address both the supply and demand sides of the light weapons equation; and 4 Canada can play an important, if modest, leadership role in mobilizing the international community to deal with the problems of light weapons. TERMS AND DEFINITIONS Although there is no authoritative definition of light weapons, by convention they are understood to be armaments that are used in intercommunal and intrastate conflict and that fall below the threshold of major conventional weapons systems (that is, those weapons encompassed by the seven categories of the United Nations Register of Conventional Arms: battle tanks, armoured combat vehicles, large calibre artillery, combat aircraft, attack helicopters, warships, and missiles/launchers).(f.3) At one end of this spectrum are 'small arms' such as pistols, assault rifles, and light machine guns.(f.4) At the other end are crew-served armaments such as recoilless rifles, mortars, light artillery, and even some missile systems. Strictly speaking, the term includes landmines, though these are often treated as a separate category, especially in the context of international disarmament negotiations. Light weapons can be found at every point along the continuum of technological complexity. At one extreme, they can be highly sophisticated and embody increasingly advanced (and lethal) technologies. The most important technological developments include reductions in size and weight; improvements in target acquisition; increased rate of fire; 'improved ballistic and terminal effects of projectiles'; 'improvements in affordability, simplicity, and ruggedness'; and reduced maintenance requirements. …