The identification of hepatitis C virus by Michael Houghton and his c- leagues at the Chiron Corporation nearly years ago represented a technical tour de force of modern molecular medicine. This breakthrough t only unearthed the causative agent of n-A n-B hepatitis that had eluded the best of scientists for more than 20 years, but also was symbolic of ather chapter in the changing paradigm of modern science and medicine. The re- lutionary concept of identifying a pathogen without actually visualizing or detecting it will forever redefine the way we approach pathogenesis of d- eases whose cause is unkwn. It is benefitting that this discovery treads on the heels of the human immudeficiency pandemic, and parallels the ala- ing emergence of various microbial pestilences in the world. Despite the rapid advances in our understanding of the virus, there is much remaining to learn about it. This book highlights some of the important areas yet to be unraveled. As illustrated in this book, the marriage between basic science and clinical medicine is essential in our quest for these unkwns. The last decade has focused on the fundamentals of the virus; the next decade must underscore translational research, bridging clinical medicine and basic science with re- ization of fundamental kwledge to improve prevention, diagsis, and tre- ment of viral hepatitis C.