The cingulate gyrus is the most prominent cortical feature on the medial surface of the human brain. The cingulategyrus forms the dorsal component of the grand limbic lobe of Broca and has a major role in most theories of emotion. Because the structure of human cingulate cortex may uncover organizational principles that pertain to the entire brain, characterizing the structural heterogeneity of human cingulate cortex has been a major challenge for neuroscience. This chapter provides an overview of the human cingulate gyrus and characterizes the cytoarchitectural features of each of its regions. It begins with a consideration of the variations in the surface morphology of the cingulate gyrus and comments on brain maps that had a significant influence on current views of cingulate cytoarchitecture. Furthermore, the chapter describes the cytological criteria for each area based on new human cases using immunohistochemical techniques. This analysis substantiated the evolving four-region neurobiological model of the cingulate gyrus. The heterogeneity of cingulate structure and function that baffled neuroscientists for generations is close to resolution, and this can provide a clear path to elucidating mechanisms of disease and their therapeutic amelioration through the study of the cingulate cortex.