Commentary: Expanding and clarifying the commognitive framework

► The theory of thinking as communication or commognitive approach was presented in a book by Sfard.
► The articles in this issue expand the reach of the original theory and its empirical base.
► Several articles in this issue are devoted to the ontogenetic development of mathematical objects.
► Two articles illustrate the more emotional and interpersonal aspects of this framework.
► The commognitive framework has much to offer mathematics education and the learning sciences.