It has long been recognized that there are certain children who have a more or less selective difficulty in learning to read. The earlier observers of this condition, among them Berkhan,1in 1885, apparently assumed that it was related to a general mental defect and described such cases as partial imbeciles (halbidiote). A more or less complete inability to learn to read, particularly when it is associated as it often is with atrocious handwriting and poor spelling, naturally enough would incline the uncritical observer to assume that the child was, if not truly defective, at least not as bright as he should be to accomplish his school tasks. Very often the logic of this explanation forms a typical vicious circle. The child is said to be feebleminded because he cannot learn to read, and his inability to learn to read is said to be because he is feebleminded. Gradually,