Autism has a peculiar fascination. One reason may be that extreme lack of social understanding is sometimes paired with extreme talent. Roughly 10% of people with autism have some special, usually very specific talent. These individuals are known as “savants”. (This term has replaced the phrase “idiot savants”. Although this nicely expressed the contrast between mental handicap and special ability, the word “idiot” has changed from a medical term to a term of abuse.) Savant abilities are very rare in people with other forms of learning difficulty. Autistic savants can show remarkable ability in areas such as art, music or mathematics. A common savant skill involves immense knowledge of calendar dates. Some individuals would be able to tell you accurately without delay what day it will be on 14 August 2048-or any other day you care to mention. One savant could pair days and dates over a period of 40,000 years (Hermelin, 2001).