The aim of this article is to revisit Ferenczi's Clinical Diary (1932) to investigate the influence he had on Melanie Klein's work. It starts from the position that insufficient recognition has been given to Ferenczi's contribution to Klein's body of work and her professional development. Her analysis with Ferenczi lasted 5 years, a relatively long analysis for the period. It explores his influence in three specific areas: the importance of raw and early emotion in the maternal bond, the importance of freedom and authenticity in the analytic relationship, and finally the use of transference and countertransference feelings. Ferenczi's ill-fated experiment with mutual analysis will be discussed as it opened up a route to explore the analytic relationship, with important consequences for the future development of psychoanalysis.