We propose a semiotic turn in distributed cognition: problem solving, cognitive agency, and cognitive artifacts are all semiosis (triadic sign-action): an emergent, temporally distributed and self-organized process of niche construction, whose morphological variety can be exhaustively described by a system of three logical-phenomenological categories and ten relational classes. In this introductory chapter, we briefly present a panorama of this book’s argument, as divided in three parts: semiotic emergence (part 1), problem-solving tasks (part 2), and meaning and niche construction (part 3).