As we continue to elucidate relationships between neural structures and cognitive functioning in this Decade of the Brain, it is important not to lose sight of the larger context. The brain is but one component of the complex system that is the body. We take in information and interact with the world through our bodies, and our bodies change with—and in some cases change—cognitive and emotional processing. In this introductory paper, we present an overview of a broad range of psychophysiological techniques: electroencephalography, event-related potentials, magnetoencephalography, positron emission tomography, optical imaging, functional magnetic resonance imaging, electromyograms, eye tracking, pupillometry, cardiovascular measures, and electrodermal activity. These techniques not only differ in their temporal and spatial resolutions but also in the physiological and psychological processes to which they are sensitive. With respect to the system as a whole, these techniques are thus complementary. Combining measures—old and new, central and peripheral—ultimately provides the most inferential power for attacking the questions we hope to answer with all psychophysiological measures in our quest to understand the nature of the relationship between the mind and the body.