Tubby Tabby always wants to be let in, and then out, and then in again. Mum gets a cat flap, and thats when the trouble begins. . . Reading Corner covers three grades of early reading ability. Compiled in consultation with Dr. Barrie Wade, Emeritus Professor of English in Education at the University of Birmingham, and Dr. Hilary Minns, Lecturer in English at the Institute of Education, University of Warwick. Each grade has three levels, indicated by the number of bars on the spine of the book. Each level has a limited number of words per story, to help you choose the right book for a young reader.