This article considers the origins of Stanislavski's system and his insistence that the actor's skills, like the musician's, must be honed through daily exercises. Such practice must become the actor's ‘second nature’, as Stanislavski terms it. Rose Whyman here compares what Stanislavski has to say about skill acquisition with the psychologist William James's discussion of the role of habit in learning. This raises some problems in theorizing the system today, as it was rooted in the science of more than a century ago, when much less was known about the mechanisms of memory and learning. Rose Whyman worked previously in community and experimental theatre and is now a lecturer in Drama and Theatre Arts at the University of Birmingham. Her book The Stanislavski System of Acting: Legacy and Influence in Modern Performance is to be published by CUP later this year.