In the past forty years, the study of grief has grown and developed. We no longer view grief as a series of universal stages – rather we now see a continuum of reactions, very personal pathways that encompass the range of reactions individuals have to loss – from resilience to more complicated forms of grief. This chapter explores the early theoretical efforts to conceptualize grief, and recent developments in the field that have led to the present state of the conversation. This chapter examines five key developments in the history of studying grief and bereavement. First, this chapter explores the seminal contributions of Sigmund Freud and John Bowlby for laying a foundation for the study of grief. Second, this chapter examines the impact of Elisabeth Kübler-Ross’ stage theory of grief. Third, this chapter discusses the ways in which Catherine Sanders’s phase theory and J. William Worden’s task model advanced the conversation beyond the stage theory. Fourth, this chapter explores four key developments in the modern understanding of grief, focusing on the extended definitions of ‘grief,’ the shift of focus beyond the Western preoccupation with affect, the movement beyond focusing on coping, and the impact of continuing bonds theory in the field. Finally, this chapter examines three current approaches to grief theory: Worden’s task model, Stroebe and Schut’s dual-process model, and Neimeyer’s approach to meaning reconstruction. As new theories of grief develop, these theories fuel new therapeutic approaches. In many ways, the last four decades have seen a renaissance in the study of grief. Hopefully as therapists and counselors become more aware of these developments, the end result will be increasing understanding and validation for individuals struggling with grief and loss.