During the closing months of an analysis, a patient suddenly began to sleepwalk. The exploring of this phenomenon, by means of a pivotal dream which ultimately connected with a severe traumatic experience of early childhood, provided confirming evidence for what had previously come out in the treatment regarding his developmental history and pathologic family milieu. Central to the over-determined meanings connected with the sleepwalking was its role as a special type of motoric dream activity which served the function of mastery of traumatic stimuli on several different levels. The exploration of this mastery function led to its linkage with such other aspects of the sleepwalking as its repetitive-compulsive basis, its similarity to the hypnotic state, and its intraphysic communicative function. The sleepwalking, the clarifying dream at its re-occurrence, and its transference reenactment all converged during the final phase of the analysis and were worked through with favourable resolution for the patient.