Mirroring is a term that has diverse application and meaning in psychological literature and practice. To clarify why this image has such widespread use, previous attempts to illustrate the psychological significance of the mirror, mirror phenomena, and mirroring behavior are explored. In addition, the work of infant researchers on specifying the mechanisms and developmental importance of mirroring in the early infant–caregiver dyad is integrated with theoretical writing on mirror transferences. Last, the historical, theoretical, and research ideas provide the bases for suggestions for clinical practice.