The prominent role played by human capital in the information and knowledge society (White paper on education and training - Towards the Learning Society, 1995), makes timely and pertinent a reflection on the multiple forms - expressed in knowing, knowing how to do and knowing how to be - in which the semantic field of this concept is articulated. In an effort to build the basis for a promising collaboration between formal knowledge and knowledge of practice; between normalized and explicitly codified knowledge and informal knowledge marked by a tacit component of knowledge, this issue brings together contributions of theoretical reflection or empirical research related to the following themes: - historical-philosophical and epistemological reflections that help clarify the relationship between knowledge and practice knowledge in different disciplinary fields; - the knowledge/practice knowledge dialectic in knowledge construction processes; - implications of the knowledge/practice knowledge dialectic on teacher education; - relationship between formal knowledge and knowledge of practice in teaching action and curricular design; - relationship between school and work in the light of the knowledge/knowledge of practice pair; - practical-perceptual and bodily dimensions of knowledge-building processes; - social and educational role of cultural craftsmanship.