Volume 5, Number 2, 1998 Contents: H. Mahn, V. John-Steiner, Introduction R. van der Veer, From Concept Attainment to Knowledge Formation. E.S. Lima, The Educational Experience With the Tikuna: A Look Into the Complexity of Concept Construction. E.A. Forman, J. Larreamendy-Joerns, Making Explicit the Implicit: Classroom Explanations and Conversational Implicatures. M. Hedegaard, Situated Learning and Cognition: Theoretical Learning and Cognition. V. Jonn-Steiner, T.M. Meehan, H. Mahn, A Functional Systems Approach to Concept Development. B. van Oers, The Fallacy of Decontextualization. W.L. Wardekker, Scientific Concepts and Reflection.