Our understanding of autism has evolved over the past forty years. In the past, autism was diagnosed using narrow criteria. Today, although it is still characterized by social and communication difficulties, rigid interests, and repetitive behaviours, the autism spectrum is much broader. There is also a growing awareness of the historical underdiagnosis of women and girls with autism. Instead of viewing autism as a single ‘disorder’ to be treated, it is increasingly discussed as a form of neurodivergence. The excerpt is from a lecture by Professor Francesca Happé CBE titled ‘Changes in the Concept of Autism’.