The work takes as its starting point Winnicott's well-known article «The capacity to be alone», which is briefly summarised so as to connect it with the development of the Winnicottian conception of the «capacity to…». This conception had no place in metapsychology and the clinical vocabulary of psychoanalysis until Winnicott used it to delineate an innovative vertex for observation. Following Winnicott, Masud Kahn, described the capacity to dream as different from dreaming or the contents of the dream, and he extended the concept of aloneness as inherent to the individual and as a technical problem with which the analyst must deal, since by assigning sense and non-sense he can ruin the interpretation, dissipating the analysand's creative potential.

KEY WORDS: Capacity to be alone, capacity to dream, capacity to play, development and power of the I, private madness, solitude, transitional space.