Bruce Henderson & Heidi Keller 
Curiosity and Exploration [PDF ebook] 

Exploration and play behaviour form the subject of thisbook, in which a wide range of research activities, boththeoretical and practical, are presented from variousfields. In particular, the emphasis on applications (forexample, in the development of software) demonstrates theintegrated approach to basic and applied research. Theauthors come from many different countries and representvarious theoretical approaches, enabling the reader toacquire an up-to-date overview of the field and thus form anopinion of his/her own regarding this field of research.