Reading and writing are operationalised by the same biological functions that are defined by the universal perspective. However, language systems differ in terms of their transparency; for example, English and French are considered opaque scripts, whereas Spanish and Italian are described as transparent orthographies. These differences are discussed in this book as part of the language specific perspective, which can, in turn, raise questions such as: “Is a dyslexic student equally impaired in any language they study?” and “Is the type of difficulty primarily dependent on the language system or is it rather a dyslexia syndrome?” This volume provides answers through a synthesis of research on reading difficulties in first and foreign languages and existing taxonomies of dyslexia sub-types.