Many children experience difficulty learning to read although they receive sufficient reading instruction. Reading difficulties that do not result from global intellectual deficits or a chronic problem of motivation are termed dyslexia. Quantifying the (world wide) prevalence of dyslexia would require a universally accepted definition and screening process, both of which are lacking. However, estimates range from 2% to 10% of the population, with higher rates found in languages with a deep orthography. Both within the fields of neuropsychology and cognitive (neuro)science there is considerable knowledge on dyslexia. The present chapter focuses on some issues which are particularly relevant for education. The reader is referred to recent reviews and reports for more in-depth evaluation such as the OECD report (2007) and a paper by Goswami in Nature Reviews Neuroscience (2006).