# Baars et al. - Essential Sources in the Scientific Study of Consciousness **Opening (not a real abstract):** Reliable scientific evidence about consciousness has often been di‰cult to find. This volume presents more than five dozen significant articles in the brain and cognitive sciences, all with a direct bearing on the subject. Our guiding idea has been to select studies that ask, ‘‘What di¤erence does consciousness make? What are its properties, and what role could it play in the nervous system? How do conscious brain functions di¤er from unconscious ones?’’ Among the published articles that satisfy this standard we have aimed for the most definitive, the pioneering, the most articulate, and the briefest. We believe they are of fundamental importance. We have thought especially about readers who are new to this fast-growing literature. Wherever possible we have looked for good introductory articles, and our own introductions are meant