Reviews the book, The Dyslexic Brain: New Pathways in Neuroscience Discovery by Glenn D. Rosen (see record 2006-02525-000). The volume begins with contributions from scholars whose significant strengths are in the area of applied science and whose research has direct implications for the development of improved interventions. Many of the authors in this volume argue that there is probably not a single disease entity deserving of the name dyslexia, as conventional wisdom suggests, but rather that there are a multiplicity of disorders of various subtypes. Reading is a complex skill involving various cognitive subprocesses: A developmental reading disorder can result from a failure in one or more of these subprocesses. However, it becomes clear rather early on in this volume that there is not currently a consensus among scholars about the precise character of these cognitive subprocesses and the corresponding subtypes of dyslexia. This impressive volume provides us with the most up-to-date research available on a disorder that affects millions. One may return here to the Callimachian warning I have cited, that a great book can cause great evil (for an application of this warning to Plato's Republic, see Popper, 1966). Because this volume is too technical for the general reader and does not provide much contextual background for the science it presents, it seems unlikely that many will judge it to be a “great book” and more unlikely still that it will cause “great evil.” However, it is a very good book, and if the science it reports leads to improved interventions that help mitigate dyslexia (and perhaps also illiteracy), that will be a very good thing.