Serial crime is an element of society that continues to disturb and fascinate scholars. There is thus a need to understand the uniqueness of serial murderers and their psychological development. The field of psychobiography is a qualitative approach to uncover the story of an individual life through greater understanding of psychological concepts. Psychobiographical research is invaluable in the application of theory to the finished lives of exemplary or enigmatic individuals to develop and test theories of human development. Jeffrey Lionel Dahmer (1960 – 1994), a cannibalistic serial killer who killed 17 young men, served as the single psychobiographical subject in this study. Dahmer was selected based on interest value, his uniqueness and the lack of a specifically academic and psychologically focused case study on his life. A qualitative psychobiographical research method was utilized in this study. The primary aim of the research was to explore and describe Jeffrey Dahmer’s personality development across his lifespan. This was achieved by applying Erikson’s (1950) psychosocial theory of staged developmental crises to the lifespan developmental process and Adler’s (1929) dynamic individual psychology to provide a more comprehensive idiographic interpretation of Dahmer as an individual. Jeffrey Dahmer’s life history was uncovered in this psychobiographical case study research through the systematic and consistent collection, analysis and interpretation of life history materials, which highlighted five significant historical periods: (a) Childhood of Fantasy, (b) The Quiet Loner, (c) Hiatus – or Build-up, (d) Seeking a Compliant Partner and (e) Arrest, Trial and Death. The two theoretical frameworks were used to discern, transform and reconstruct his life into a coherent and illuminating narrative of his psychological movement through life. Alexander’s (1988) model of identifying salient themes was used to analyze data for analytical generalization (Yin, 1994). A conceptual framework derived from the two theoretical perspectives was constructed to organize and integrate data and to guide the presentation and discussion of the findings of the study in an integrative and comprehensive manner. The findings suggested that both theoretical perspectives considered the biopsychosocial as well as cultural and historical influences of situations and experiences in Dahmer’s personality development throughout the lifespan. Adlerian theory indicated that Dahmer held a socially useless lifestyle whose movement was guided purposively towards a fictional goal xxii of godlikeness through creative, concrete expressions of personal superiority. Eriksonian theory held that Dahmer remained in role confusion, which was viewed as a functional, fragmented identity to survive in society and achieve a fantasy. Thus, both theories indicated, despite their different conceptualizations, that Dahmer’s personality development was ultimately not socially beneficial. The study of Dahmer’s personality development has provided a positive demonstration of the value of both Erikson (1950) and Adler’s (1929) theories to understand the processes of personality development in an individual life. It has further highlighted the uniqueness of individual responses to life tasks and consequently unlocked the possibility of perceiving people and their actions differently. Recommendations were made for future research undertakings that utilize a psychobiographical research design and methodology to uncover, illuminate and reconstruct the lives of enigmatic personalities.