Mankind studied and analyzed knowledge and learning since its first history and two main ways of thinking imposed very early: idealism, interpreting reality as the construction of human mind, and empiricism, looking at knowledge as the effect of the human-reality interaction. Recently three ways of interpreting thinking and knowledge intervened in changing the above perspective: relativism (it is impossible to objectively, universally, and absolutely know), critical theory (knowledge is mediated by social, political, cultural, economical, ethnical, and gender agents), and constructivism (knowledge is built by individuals and groups, and it is socially and experientially founded). Among the above theories, constructivism played a great role in interpreting both individual and social learning and had a great influence on hypotheses explaining knowledge construction and evolution in communities, including communities of practice. The bases for today’s constructivist theories can be found in many studies. Dewey (1949), for example, was the first scientist looking at the teaching-learning process in a pragmatic way. The inquiry was for Dewey the essential element of the subject-reality interaction; the experimental method had to guide teachers’ work and students’ learning, and at the basis of the knowledge process, there had to be the theory of research. Individuals’ knowledge was continuously developing from common sense (traditions, popular misconceptions, etc.) to scientific knowledge. Main consequences of Dewey’s educational project were activism with school-laboratories and active schools. Dewey’s ideas were collected and amplified by Kilpatrick, who introduced the project as a general method of learning (i.e., problem-finding had to be used together with problem-solving in everyday teaching). The hypotheses of Dewey and Kilpatrick were born in North America, but soon spread in Europe, where they found a rich soil and differentiated in at least two threads. Binet, Decroly, and Claparède privileged the psychological aspects of activism; on the contrary, Freinet and Freinet favored its social aspects (Varisco, 2002). “Modern School” was the name that Freinet and Freinet gave to their educational project; they hypothesized the creation of a cooperative school within which the social techniques and practices—like typography, correspondence, and cooperative catalogues—had a special relevance (their experiences had counterparts in many countries, and the case of don Milani in Italy is just an example for them).