This paper reviews seven research studies on the subject of readability. The first study reviewed is itself an extensive review of 30 readability formulas described by George A. Klare. Of these, five formulas considered to be interesting, unusual, or classic on the basis of high validity, simplicity or complexity, common or uncommon variables, and other unusual features were chosen for analysis. The five formulas include those by I. I. Lorge (1939), G. D. Spache (1953, 1974), W. B. Elley (1969), J. R. Bormuth (1966, 1969), and Harris-Jacobson (1975). In addition, the initial research on cloze procedure by W. L. Taylor (1953) is reviewed to give balance to the overview of readability research. Each review consists of an analysis of the research backing the formulas, specifically the theoretical framework, the research design, the results, the author's evaluation, and a summary including comments on the usefulness and the face validity of the formulas. After the reviews, a synthesis of the studies attempts to answer the following questions: (1) What is readability and how is it calculated? (2) How good is the research on readability--what are its strengths and limitations? (3) How do readability measures compare? and (4) What are some practical implications for use of these formulas? (HOD)