The research reported, considers the problems that dyslexics have with reading and spelling and attempts to explain these difficulties as being a specific manifestation of a wider limitation in processing all forms of information. The phenomena of dyslexia is reviewed from the stand points of symptomatology and aetiology. Research work in the areas of short--term memory and information processing is reviewed. Recent research on the application of information processing techniques to dyslexia is also reviewed. Haber and Hershenson' s model of information processing is adopted as the frame of reference for the experimental investigation. The experimental investigation explores the hypothesis that dyslexics are characterised by a small capacity short-term memory and a small input channel capacity. Seven experiments are reported that test this hypothesis: (1) the processing of item and order infor-mation in visually presented digit strings by dyslexics; (2) the use of visual imagery by dyslexics, and the effect of delay on performance; (3) the processing of auditory signals of varying set size under direct and delayed recall conditions by dyslexics; (4) the direct processing of varying forms of information as measured. by encoding speed for dyslexics; ( 5) the performance of dyslexics in recognising digit, letter and symbol arrays which were presented for varying brief exposures; (6) the immediate recall by dyslexics of high redui1.dancy and low redundancy words and trigrams; and finally ( 7) the simple reaction times of dyslexics for auditory, visual and auditory/visual stimuli. The results show that dyslexics' performance on all these tasks is inferior to that of matched controls. The hypothesis is therefore accepted. A model based on the hypothesis is presented. The validity of the model is then substantiated by reference to the current research literature. It is therefore concluded that dyslexia can be considered as a general limitation in the ability to process large amounts of information quickly because of capacity limitations in short-term memory and input channels.