The elucidation during the latter half of the 20th century of the mechanisms by which information flows from nucleic acids to proteins has completely changed the face of biological research. Many diseases are caused by abnormalities in control mechanisms which are not immediately essential for life itself but which maintain the normal social behavior of differentiated cells in multicellular organisms. The complex sugar chains of glycoproteins and glycolipids are believed to play important roles in the control of cellular functions and in recognition between the cell and its cellular and fluid environment. Investigations into the abnormalities of complex sugar chain assembly are expected to yield an important new underatanding of the etiology and pathogenesis of human diseases. This volume discusses several representative diseases which emphasize the current status of glycopathology, and will stimulate further research in this exciting field.