Throughout the world, military reserves are changing. National governments are transforming the relationships between their active and reserve components, the allocation of roles and responsibilities among reserve forces, and the way they train, equip, and employ reservists. Nations no longer consider their reservists as primarily a strategic asset for mobilization during major wars. This increased reliance on reserve components presents national defense planners with many challenges. Recruiting and retaining reservists has become more difficult as many individuals have concluded they cannot meet the increased demands of reserve service. Reservists are increasingly deployed on foreign missions at a time when expectations regarding their contributions to the management of terrorist attacks, natural disasters, and other domestic emergencies are growing. Defense planners must also continue to refine the optimal distribution of skills and assets between regular and reserve forces. Finally, national governments must find the resources to sustain the increased use of reservists without bankrupting their defense budgets or undermining essential employer support for the concept of part-time soldiers with full-time civilian jobs. The author analyzes the innovative responses countries have adopted to manage these challenges.