This chapter shows that it is possible to have multiple, and perhaps quite divergent, perspectives on the nature of learning disabilities. Disagreement and varying perspectives on the concept of learning disabilities have been part of the field since its beginning. The theory of nonverbal learning disabilities developed by Byron Rourke is also a coherent theory of the nature of a particular learning disability, but it does not contain adequate description of the problem at the level of cognitive processing operations. Phonologically based reading disabilities are primarily manifested at the level of overt reading ability by difficulties acquiring alphabetic or phonetic reading strategies. On the surface, the diagnostic implications of the theory of phonologically based reading disabilities are relatively straightforward. One of the major advantages of a sound, multilevel theory of phonologically based reading disabilities is that it provides a way to diagnose the disability before children experience failure in learning to read.