Mrs Tustin is remarkable in her use of straightforward language to describe the autistic state of mind. Her way of conceptualising the unthinkable, ‘unconceptualised experience’ of the autistic child gives us access to that which lies behind the protective barrier which, she says, is erected by the child in the face of unbearable traumatic experience. She tells us how, having taken into account the findings of Brazelton, Bower, Trevarthan, and Stern, she has modified her previous views of