In this book discussion, we will discuss Borderline: The Biography of a Personality Disorder (Beacon Press, 2024), authored by Alexander Kriss, PhD. The presentation will consist of a conversation between the author and J. Christopher Fowler, PhD. Drawing on psychoanalytic theory, patient narratives, and shifts in psychiatric authority from antiquity to present day, the book explores how BPD emerged as a diagnostic concept and what its persistence reveals about the changing boundaries of identity, suffering, and care. The discussion will reflect on the tensions between diagnosis and personhood, the role of psychoanalysis in shaping and responding to BPD, and the ethical stakes of treating a condition so often marginalized—even within mental health systems.