Three most general conditions for successful acting have been established: containment of the activation of the actor's nervous-psychological apparatus within certain optimal limits, correlation of the dynamic characteristics of the actor's emotional state in the process of performing a role with the dynamics of the mental "unfolding" of the role's life circumstances in the form of images, presence of a super-goal: creative need for communication at a high level of generalization. The three conditions are shown to be closely connected with the fundamental concepts in K.S. Stanislavsky's system as well as with specific manifestations of activity and self-regulation which, on the one hand, opens a way for a psychological interpretation of K.S. Stanislavsky's system and, on the other hand, for an experimental study of actor's abilities.