This study presents an overview of the development of the main psychoanalytic conceptions regarding safety, an aspect that has received increasing attention within the psychoanalytic literature. After describing the hypotheses of Sigmund Freud, Joseph Sandler, John Bowlby, and Harry Stack Sullivan, the study focuses on the ideas proposed by Joseph Weiss and on control-mastery theory (CMT), a cognitive-dynamic relational theory of mental functioning, psychopathology, and psychotherapy. Unlike other models, CMT stresses that human beings need to feel that both themselves and the people they love are safe; each person, however, may need something different to feel safe. Two clinical vignettes are used to illustrate how the therapist can understand, from the outset of the therapeutic process, how to help the patient feel safe, stressing the case-specific nature of the conditions of safety.