Handedness, or manual laterality of function, is thought to be both universal and unique to humans, making it a highly derived trait based on an equally specialized neural substrate. By contrast, in various non-human species, both living and extinct, the extent of lateralization varies. All known populations of living human beings apparently favor the right hand motorically, culturally, and symbolically; thus, right-handedness is species typical, as well as species specific. This laterality of function is correlated with asymmetry of neural, skeletal, and muscular structure, as manifest for example in skilled movement such as handwriting. Human brains are lop-sided, and sagitally-paired organs (e.g., hand, foot, eye, ear) are skewed in their use, usually biased to the right; explaining this variation appears to require both cultural and environmental causal variables. To tackle these questions and advance our knowledge of this basic human trait requires genuinely multidisciplinary input by scholars willing to think interdisciplinarily. Thus, the authors of this Annals issue come from anthropology, archaeology, genetics, neurosciences, palaeoanthropology, primatology, psychology, and psychiatry.