Interest in developing an effective communication interface connecting the human brain and a computer has grown rapidly over the past decade. The brain-computer interface (BCI) would allow humans to operate computers, wheelchairs, prostheses, and other devices, using brain signals only. BCI research may someday provide a communication channel for patients with severe physical disabilities but intact cognitive functions, a working tool in computational neuroscience that contributes to a better understanding of the brain, and a novel independent interface for human-machine communication that offers new options for monitoring and control. This volume presents a timely overview of the latest BCI research, with contributions from many of the important research groups in the field. The book covers a broad range of topics, describing work on both noninvasive (that is, without the implantation of electrodes) and invasive approaches. Other chapters discuss relevant techniques from machine learning and signal processing, existing software for BCI, and possible applications of BCI research in the real world. Guido Dornhege is a Postdoctoral Researcher in the Intelligent Data Analysis Group at the Fraunhofer Institute for Computer Architecture and Software Technology in Berlin. José del R. Millán is a Senior Researcher at the IDIAP Research Institute in Martigny, Switzerland, and Adjunct Professor at the Swiss Federal Institute of Technology in Lausanne. Thilo Hinterberger is with the Institute of Medical Psychology at the University of Tübingen and is a Senior Researcher at the University of Northampton. Dennis J. McFarland is a Research Scientist with the Laboratory of Nervous System Disorders, Wadsworth Center, New York State Department of Health. Klaus-Robert Müller is Head of the Intelligent Data Analysis group at the Fraunhofer Institute and Professor in the Department of Computer Science at the Technical University of Berlin.