The Human Security Network (HSN) represented an innovative attempt at flexible multilateralism, working with a small group of like-minded states. This article traces its origins and evolution, in particular, in the campaign to ban anti-personnel land mines) and examines the process of developing and implementing policy-in and beyond the HSN. The HSN struggled to develop a coherent and focused human security agenda and distinguished itself somewhat from other international efforts to define human security. In several different areas (like small arms, the "responsibility to protect" and the civilian protection agenda) the HSN can be shown to have been at the genesis of several concrete initiatives. It has been somewhat less successful at institutionalising its interactions, and in embedding a vision of human security in the foreign policies of participating states. Finally, the article explains how a full appreciation of the impact of the HSN requires examining not just its formal diplomatic and political efforts (which have had limited results), but its broader contribution (along with many other actors) to the setting of the human security agenda worldwide.