Autism as a disorder has baffled and fascinated investigators since it was first identified by Kanner. The peculiar nature of the problem is that it is not visible in the way that a physical difficulty is. And, in contrast to sensory deficits, the sources of the difficulties are not obvious. Autism is inferred purely on the basis of its behavioural effects and the patterns and combinations of these behaviours observed in varying contexts. During the last two decades or so some extremely interesting theories have emerged attempting to explain what may be altered, preserved, impaired or even enhanced in the developing mind of the young child with autism. To us as educators theoretical explanations of the difficulties inherent in autism are not merely interesting; they are, indeed, vital to our practice. Without a coherent working model of the processes that may be at work to produce the behaviours typical of autism, we are reduced as educators to a piecemeal approach, tackling individual behaviours one at a time, or following ‘recipes’ for successful teaching. The problem with the latter approach is that when a difficulty occurs because the child does not respond as suggested by the ‘recipe’, the teacher has no framework of understanding or underlying principles to help guide amended or alternative strategies. Ironically, as Powell and Jordan (1997) crisply state, ‘such educationists then find themselves in the same position as an individual with autism: unable to step outside of the learned routine and at a loss as to how to proceed next’. Along with Jordan and Powell (1995), the present authors, therefore, would argue for an educational approach that takes full account of the specific ‘autistic’ way of thinking and learning, and for autism as a different culture – another dimension. In outlining the following proposed explanations or models of functioning in autism at the psychological level, it is the authors’ intention that they should serve for the reader as a set of lenses through which autism may be perceived. In our previous book (Cumine et al. 1998) we used the image of the Asperger lens to invite the reader to note how behaviours interpreted from an ordinary, non-autistic point of view will look very different when viewed from the point of view of the person with autism. More importantly, our responses to the behaviour are dramatically altered. In arriving at an understanding of the world from the viewpoint of the person with autism it is our contention that several ‘lenses’ of interpretation may need to be tried. Rather as on a visit to the optician, several different lenses will be inserted, sometimes separately, sometimes in combination, in order to bring the letter chart into clear focus.