The Phantom Limb by William Sleator and Ann Monticone.
Sleator and Monticone have woven a story out of illusions. Things are not what they seem throughout the book, as is the case with many Sleator books. They begin with Isaac and his interactions with the Fizpatrick twins, who seem to take joy and pride in being as nasty as possible. Then they introduce us to Isaac's optical illusion room. Isaac finds what he calls a "mirror box" in the house in which the family (which consists of mother, grandfather, and Isaac). in researching this box he finds that it is used therapeutically for people with problems resulting from an amputation. He gets to try it out and plays with it to while away the time. Isaac's mom is in the hospital because she has developed seizures, and his grandfather seems to be suffering from dementia.
The story seems plausible given Sleator's penchant for the use of both strong science and eery interactions with what can be seen as supernatural. However, the character development is weak and one wonders whether this title was rushed to print too soon because of Sleator's death. There are unexplained situations, such as why the grandfather seems to get better through the book, why the Fitzgerald twins' (a term I hate because it seems to refer to them as a single entity, when they clearly are not) behavior is so heinous, and why Isaac's mother actually has seizures. Too many loose ends for me.
I enjoyed this book. It is a typical Sleator, and if you are a fan, will give you pleasure to read it.
