Congress continues to register concern about the rapid rise in Medicare spending and the ability of existing funding mechanisms to support the program over the long-term. A combination of factors has contributed to the rapid increase in Medicare costs. These include increases in overall medical costs, advances in health care delivery and medical technology, the ageing of the population, and longer life spans. The issues confronting the program are not new; nor are the possible solutions likely to get any easier. For a number of years, various options have been suggested; however, legislative changes have focused on short-term issues. There is no consensus on the long-term approach that should be taken. This book provides an overview of Medicare. It begins with a brief program history, and then outlines the key features of Parts A and B, also known as "Original Medicare". That is followed by overviews of Part C and Part D, a discussion of program financing, and a brief discussion of future program directions. It will be updated to reflect any legislative changes.