School psychologists are often involved in evaluating students who have been referred for reading problems or are suspected of having dyslexia. To accomplish this task, it is important to have a thorough understanding of dyslexia, and know what factors to consider. Therefore, the purposes of this article are to describe: (1) the primary and secondary characteristics of dyslexia; (2) the most common cognitive and linguistic correlates; and (3) the concept of unexpectedness (the ability to learn when reading is not required).