The major purpose of the proposed studies is to further evaluate hypothesized differences between poor and normal readers in three major areas of concern: verbal memory, lexical development and receptive and expressive syntax. In the area of verbal memory the primary objective is to edify and add detail to results from our laboratory that suggest that younger and older poor readers are differentially impaired by deficiencies in encoding and retrieval processes on short- and long-term memory tasks. As regards lexical development, our primary aim is to evaluate the degree to which reader group differences in vocabulary development may influence group differences in verbal memory and word identification. As for syntactic competence, studies already initiated provide compelling evidence that poor readers, as old as 9 and 10 years of age, suffer basic deficits in critical areas such as knowledge of English morphology and expressive syntax; thus certain of the studies proposed seek to extend this inquiry to include comprehension of syntax. The second major objective of the present project is to further evaluate the claim that significant discrepancy between the WISC Verbal and Performance IQ's is a valid index with which to define separate dyslexia syndromes. There are fourteen separate projects proposed to accomplish the above objectives, each involving one or more experiments contrasting poor and normal readers between grades 2 and 6 inclusive.