This monograph, first in a series of six, provides the theoretical background and premises underlying the efforts of the research team and two collaborating California school districts to explore ways in which the computer and related technologies can be more fully and effectively used in the instruction of learning disabled students. Contents include the following: (1) an analysis of key theories about mental functioning and remediation; (2) a definition of learning disability and consideration of commonly associated variables (genetics, maturation, drug effects, trauma, laterality and hemispheric dominance, sex differeces, orthography and handwriting, and sensory integration); (3) an examination of visual perception, functional vision, and reading efficiency; (4) cognitive processes (including memory, problem solving, and task strategies); and (5) promising computer applications (including use of the computer for vision training, perceptual enabling skills, and cognitive processing skills). (JW)