Technology has long been a helpful aid in human cognitive activities. With its growing sophistication and usage, technology is now taking a more intrinsic and active role in human cognition. The shift from an external aid to being an internal component of cognitive processing reflects a revolution in technology, cognition, and their interaction. The creation of such ‘cognitive technologies’ transforms the traditional instrumental function of technology to a constitutive role that shapes and defines cognition itself. This book, which was originally published as a Special Issue of Pragmatics & Cognition 13:3 (2005), explores the new horizon of these ‘cognitive technologies’ and their interactions with humans.