Orthographic knowledge can be regarded as stored information about the regularities and exceptionalities of the spelling system, and orthographic processing skill as the ability to use such information efficiently in a range of reading and spelling tasks. This paper focuses on the role of orthographic processing skill in adults' reading proficiency. A case study is discussed in which orthographic processing skill was perfected despite phonological deficiencies, allowing highly skilled silent reading. Data are also presented which indicate that orthographic skill plays a significant independent role in fluent reading aloud of connected text. The importance of studying the various aspects of orthographic processing capability and their contribution to the process of attaining adequate literacy competence is stressed.