The excerpt begins like this:
Dear Dr. Sacks,
My (very unusual) problem, in one sentence, and in non-medical terms, is: I can’t read. I can’t read music, or anything else. In the ophthalmologist’s office, I can read the individual letters on the eye chart down to the last line. But I cannot read words, and music gives me the same problem. I have struggled with this for years, have been to the best doctors, and no one has been able to help. I would be ever so happy and grateful if you could find the time to see me.