Chapter 1 provides an overview of the aims of the book, and the coverage in the chapters contained within the book. It includes a brief introduction to dyslexia, starting with the key features of dyslexia, primarily as seen from research and practice on children, before moving to a discussion of adult dyslexia. These key elements related to dyslexia focus on difficulties with reading and writing that can be long-lasting, and hence occur in adulthood. They also link to the potential cause of dyslexia, such as phonological processing deficits, and the impact that dyslexia can have on learning and cognition in general. Therefore, the chapter also discusses issues related to the experiences of adult dyslexics and the consequences of dyslexia that can impact on life and performance in the workplace. Dyslexia in adulthood can be considered more complex to childhood dyslexia given the range of experiences and strategies that the individual has acquired, as well as the variability in tasks that the adult needs to perform. Hence, individual differences in strengths and difficulties, as well as lifetime experiences, are an important for understanding adult dyslexia.