Combining the research talents of many long-standing members of the Association for the Study of Play, this work provides discussions of the theory and applied value of play, as well as ongoing research from America, Australia, Taiwan, and Korea. The developmental and educational theories of Lev Semenovich Vygotsky are analyzed in several chapters. The world's premiere play scholar, Brian Sutton-Smith, continues his seminal play theory work, following up on previously presented findings and constructing a developmental theory of play based on emotions.