In this chapter, we follow out the implications of the argument in the first chapter concerning the developmental mechanisms that produce mentalization and reflective function. Here we examine the relationship of early object relations with mentalization through the lens of affects and affect regulation. This chapter provides a historical overview of academic traditions concerning affects and affect regulation from the perspective of mentalization. The chapter is not intended as any kind of exhaustive review—an ambition that is substantially beyond the scope of this work. Our aim here is to point to key controversies in the study of emotion. The review highlights the fact that analogous dichotomies exist across a number of disciplines. Both philosophical and psychological traditions tend to regard affects in one of two ways: (a) ideally as integrated with cognition, and (b) as inherently independent of, opposed to, and out of the control of rational thought. Certain neuroscientists have suggested that both traditions may have strong foundations in the brain structures assumed to mediate emotional experience. Psychoanalysts, including Freud, have also pursued both lines of thought, with notable individual exceptions. We review the contribution of attachment theorists in some detail, since this framework represents the starting point for many of the ideas in the current 66monograph. In the attachment theory tradition, there is a commitment to explore precisely how affective experience contributes to the acquisition of self-regulation by virtue of coregulation between caregiver and infant. The present chapter places our approach, which is also based in the developmental tradition already outlined briefly in chapter 1, into a historical frame of reference, insofar as we attempt to integrate the two major intellectual traditions concerning affect.