The last decade of research on the biological bases of reading has generated an exciting quilt of findings integrating what we currently know about the biological machinery behind the skill of reading. This machinery is impressive in many aspects, but mostly in its robustness. Given its complexity, it is quite amazing how relatively rarely it breaks down. In fact, there are relatively few cases in the literature of individuals who are absolutely unable to read. And most, if not all, of these cases present some other fundamental developmental problems, such as severe mental retardation. If taught, the overwhelming majority of people can learn to read, at least to some degree. Yet people exhibit significant variation in their number of errors when reading aloud, in their speed of reading (both aloud and silently), and in their degree of comprehension of the written material.