Book excerpt: Humans possess a remarkable ability to extract rich three-dimensional information about sound environments simply by analyzing the acoustic signals they receive at their two ears. Research in spatial hearing has evolved from a theoretical discipline studying the basic mechanisms of hearing to a technical discipline focused on designing and implementing increasingly sophisticated spatial auditory display systems. This book contains 39 chapters representing the current state-of-the-art in spatial audio research selected from papers presented in Sendai, Japan, at the First International Workshop on the Principles and Applications of Spatial Hearing.