Addie and her older sister, Keedie, are both autistic, but with the higher form that is often called Asperger's. Keedie is a twin, but Nina is very different. She does make-up and clothes styling in an online blog, while Keedie is at University. Addie is still in top class in her primary school and suffering from serious bullying from a girl in her class and from her teacher, but luckily there is a kind librarian who finds her books about her special interest in sharks. Addie and Keedie are best friends as well as sisters, partly because they understand each others problems, and Addie feels she can tell her sister anything. Nina is a very different kettle of fish, and while she loves both girls, she finds living with them difficult. The parents are supportive and loving but are more shadowy. The strength of this novel, told by Addie, is that we learn to understand why people with autism think and act the way they do, both from Addie's inner thoughts and from her conversations with Keedie. When Addie begins to learn about witches in their village near Edinburgh during a school project, it becomes her new favourite subject, and she learns all she can about local witches who were executed during a witchcraft hunt. She begins to feel they were people who were 'different', just as she is, and in the process wants to have a village memorial to them. Her fight to reach her goal makes up a great deal of the novel. This is meaty stuff, well-written and evocative of what it must feel like to be autistic - not surprising as the author is herself autistic. And one of the themes in the book is that Addie emphasises the fact that she IS autistic, not that she has autism as though it were a disease. An excellent page-turner and a moving story.