This contribution is dedicated to the Russian psychoanalyst Sabina Spielrein (1885-1942). Following a short sketch of the historical context, we focus on Spielrein’s oeuvre, with specific reference to the implicit and the explicit impact of both Spielrein and her earliest work on the thinking of Jung and Freud. We concentrate not only on the theme of (counter)transference and on the concept of the death instinct, but also on some typically Jungian core concepts, such as the “collective unconscious”, the “archetypes”, the “anima”, and the “shadow”. In addition, we also briefly discuss Spielrein’s pioneering work in child analysis, including the role of child play, infant observation, and developmental psychology. In this way, we hope to illustrate the concrete impact of Spielrein’s oeuvre on the work of Melanie Klein, Anna Freud, and Donald Winnicott.