A framework for a comprehensive theory of reading is presented in this paper. The framework consists of perceptual, semantic, and control systems. The perceptual and semantic spaces of the theory should not be confused with the terms "decoding" and "comprehension"; decoding and comprehension refer to ways in which those spaces are utilized, requiring specific task demands and stages of practice within those spaces. The third part of the human information processing system is the collection of basic operations and learned programs for performing reading tasks in the other two spaces; in effect, this control system is like a computer program, directing attention to and providing directions for performing a perceptual or semantic reading task. A discussion of each system within the theory, including relevant research, concludes with a taxonomy of reading tasks and the implications of the whole theory for reading research. Discussion following presentation of the paper is included. (RL)