Part Four: Chapter Twenty-Three, The Twins Summary and Analysis

John and Michael are twins who have been in and out of various institutions since the age of seven. Dr. Sacks meets them in 1966 when they are twenty-six years old. The twins are semi-famous, having appeared on radio and television shows to showcase their savant-like ability to "say at once on what day of the week a date far in the past or future would fall." Interest in the twins begins to wane but Sacks continues to enjoy "studying" the twins in a more laidback manner.

The twins have been subjected to numerous tests in order to understand their unusual ability. They have become a carnival sideshow for people wanting to play with their ability to calculate the date of Easter for the next 80,000 years. As outstanding as this ability is...