This volume is based upon a conference which brought together a group of leading developmental researchers to assess state-of-the-art methodology for measuring audition and vision during the first year of life. The volume is primarily aimed at providing an overview of current methods used to assess hearing and vision. Both behavioral and physiological approaches are examined in detail with a view toward providing the reader with a critical undertanding of the methods, including their strengths and weaknesses. It is essential reading for those interested in the development of sensory systems.