There are major changes taking place in the way elderly and disabled people pay for prescription drugs. These changes are being ushered in by the new Medicare law, which, if it lives up to its promise, will be incredibly helpful to some of the most vulnerable members of our society. What are the details of the new law? How many people will it affect? How will low-income people be assisted? What are the implementation challenges? How are they being addressed by the federal government? What can grantmakers do to help?