As a discipline, psychoanalysis began at the interface of mind and brain and has always been about those most basic questions of biology and psychology: loving, hating, what brings us together as lovers, parents, and friends and what pulls us apart in conflict and hatred.These are the enduring mysteries of life and especially of early development-how young children learn the language of the social world with its intertwined biological, genetic, and experiential roots and how infants translate thousands of intimate moments with their parents into a genuine, intuitive, emotional connection to other persons. Basic developmental neuroscience and psychology has also of late turned to these basic questions of affiliation: of how it is that as humans our most basic concerns are about finding, establishing, preserving, and mourning our relationships. These areas in broad strokes are the substance of mind and brain, and the last decade has brought much new science to the biology of attachment, love, and aggression. These are areas that practicing psychoanalysts have long been immersed in and have much to say about - and contemporary neuroscientists and developmentalists are recognizing the importance of understanding these basic issues at a deeper, and more subjective experiential level. The challenges before us are how to facilitate open discourse and collaborations among these perspectives and practitioners that often work at very different levels of discourse. This volume is not only a first step in that process but also, through the themes of the chapters and the pairing of discussants, a beginning illustration of how the cross-disciplinary discourse might work.