Cognitive systems may be described as technology in support of cognitive abilities or as tools for thinking. The entire range of such technologies is large and crosses a wide variety of disciplines. In this article, an outline for bioengineering contributions to cognitive systems will be provided. In the discipline of engineering, several areas are dedicated to development of tools for cognition, such as human–computer interaction, ergonomics, and many components of computer science. Beyond engineering, many disciplines are dedicated to the study and improvement of thinking, from education and psychology to neuroscience and cognitive science. Bioengineering contributions to cognitive systems combine the engineering approach to human–computer interaction with the biophysical information from neuroscience and cognitive science. In this article, the functional aspects of cognitive science will be reviewed: basic physiology of the nervous system, sensory inputs, motor control, and the cognitive functions: attention, memory, language and speech, emotion, consciousness, and higher cognitive functions. How we might interact at a bioengineering level with cognitive processes involves working with the brain as an organ and detecting its action: through behavior and direct recording methods. Finally, bioengineers should keep applications of cognitive science in mind as technologies are developed to interact with the brain.