In 1988, the film Rain Man," about an autistic savant played by Dustin Hoffman, shed a humane light on the travails of autism while revealing the extraordinary powers of memory that a small number of otherwise mentally disabled people possess, ostensibly as a side effect of their disability. It never would have been made if [Barry] Morrow had not had a chance meeting with Kim Peek, who inspired him to write the film. Mr. Peek, who was dismissed as mentally retarded as a child and later misdiagnosed as autistic, led a sheltered life, with few people outside his family aware of his remarkable gifts. Mr. Peek was not autistic - not all savants are autistic and not all autistics are savants - but he was born with severe brain abnormalities that impaired his physical coordination and made ordinary reasoning difficult. He could not dress himself or brush his teeth without help. He found metaphoric language incomprehensible and conceptualization baffling. But with an astonishing skill that allowed him to read facing pages of a book at once - one with each eye - he read as many as 12,000 volumes. Even more remarkable, he could remember what he had read. Almost all documented savants - people with an extraordinary depth of knowledge and the ability to recall it - have been restricted in their expertise to specific fields like mathematics, chess, art or music. But Mr. Peek had a wide range of interests and could instantly answer the most arcane questions on subjects as diverse as history, sports, music, geography and movies.