Who is Dr. Oliver Sacks from The Man Who Mistook His Wife for a Hat and Other Clinical Tales and what is their importance?

Dr. Oliver Sacks is the author of the book and also a character in all of the stories. Although he is a character, Sacks is not the main character. Sacks, a neurologist, is only the medium through which the other characters are able to come alive for the reader. It is through Sacks' unique blend of clinician and humanitarian that many of the characters in the book become more than just patients.