Designing systems that change the way we perceive, think, and act in our immediate surroundings. I explore the development of mobile and wearable systems that seamlessly blend with and support ongoing real-world tasks (c.f. Mark Weiser’s vision of calm computing) and give rise to what we refer to as an egocentric interaction paradigm. I believe that human perception, cognition, and action capabilities are defining factors for future wearable systems that talk to us in increasingly subtle ways through our peripheral attention. Keywords: Human-Computer Interaction, Peripheral Interaction, Ubiquitous Computing, Wearable Computers, Augmented Reality, Artificial Intelligence.