The first part of this paper explains the distinction between proximal and distal causes of developmental disorders of cognition, with special reference to developmental disorders of reading. A number of different proximal causes of developmental disorders of reading have been identified. These correspond to a number of different patterns of developmental reading impairments--a number of "types of developmental dyslexia", if you like--which are described in the second part of the paper. These patterns are interpreted in relation to a specific information-processing model of the cognitive system for reading. How each pattern is diagnosed, and how each might be treated, is discussed.