This year marks the tenth anniversary of the International Symposium on Medical Virology. In the Foreword to the book of the 1980 Symposium, we stated, "However, the challenges still lying ahead are more numerous than our past accomplishments." Little did we know at the time, that within a few years the spread of human immunodeficiency virus type I was going to occur. This worldwide epidemic has, like no other disease in recent history, awakened the scientific community and the public at large. It is a reminder to all of us that regardless of our vast technical advances, Nature provides such...