The methodology section describes a plan for the application of a classification model to the investigation and development of a subtyping nosology for reading disorders (dyslexia). The Methodology Core constitutes one section of a larger proposal designed to: 1) identify subtypes of reading performance within a broad population of children with learning difficulty whose deficient test performance is below expectation in reading and/or math, or who meet accepted criteria of attention disorder; 2) address the neuroanatomical correlates of reading disabilities through state-of-the-art magnetic resonance imaging of the brain; 3) provide a quantitative index of shared electrophysiological activity that assesses communication across brain areas through the use of EEG coherence analysis; 4) examine the emergence of subtypes of reading disability in an epidemiological sample and within a longitudinal framework; and 5) investigate individuals within reading disability subtypes who have affected family members in order to clarify possible genetic influences on reading disability.