Justice is the foundation of liberty. Thus, the proper functioning of our criminal justice system is a vital concern for all who value liberty. When figures such as David Hume first laid down the classical liberal principles which form the foundation of our criminal justice system, however, scientifi c evidence did not yet have the important role in criminal cases that it does today. Since the beginning of the twentieth century, that importance has grown so much that forensics is now a central function of the criminal justice system in the United States and in courts around the world....