An Anthropologist on Mars is the sixth book by neurologist Oliver Wolf Sacks and deals with seven intriguing case studies. The first is an artist who becomes completely colour-blind (cerebral achromatopsia) and details both the unimaginable impact this has on normal life, and the adaptation that can make life liveable. The second involves amnesia and looks at different ways of forming memory. The third deals with Tourettes syndrome in a surgeon with a pilots licence, shows both the funny and the dark sides of this condition, and the effect of medications. The fourth examines the effect of regaining sight on a person who has been blind since childhood. The fifth involves seizures of reminiscence and examines what memory actually is. The sixth deals with an autistic savant artist, and the final case study is about the well-known Aspergian, Temple Grandin. It is this remarkable woman who, in explaining what it feels like to try to understand normal human behaviour, lends her phrase to the title, An Anthropologist on Mars. Grandin gives a fascinating insight into the autistic spectrum, explaining that autistic people Think in Pictures (the title of her own book). Occasionally Sacks is rather too generous with technical detail jargon, so the reader may be tempted to skim or skip. The footnotes enlarge on or update the text, the book is fully indexed and there is a bibliography for those interested in further reading. This book is interesting, occasionally scary and will make the reader appreciate the brain they have.