This book is the outcome of a long and passionate debate among world experts about two of the most pivotal figures of psychology: Jean Piaget and Lev Vygotksy. The occasion was a week-long advanced course held at the Jean Piaget Archives in Geneva. The most interesting outcome of the meeting is that, in spite of differences in aims and scopes (epistemogenesis versus psychogenesis), in units of analysis (events versus action) and in social contents (Swiss capitalism versus Soviet communism) both Piaget and Vygotsky reached a similar conclusion: knowledge is constructed within a specific...