This appraisal of the readability of materials used by Adult Basic Education (ABE) teachers determines readability by using the Dale-Chall Readability Formula, the Fry Readability Graph, and the Gunning Fog Readability Formula. An introductory chapter states the problem, defines terms, and presents the importance, hypotheses, design, limitations, assumptions, and organization of the study. Chapter 2 is a review of related literature; chapter 3 describes the procedures used; chapter 4 is a presentation and interpretation of the data; chapter 5 contains a summary, conclusions, and recommendations. A bibliography and four appendixes are included. The study found that formula estimates, teacher judgments, and publisher ratings do not consistently support each other when measuring the readability of instructional materials. The data suggests that ABE teachers need to use a combination of assessment measures to select the best instructional materials. It is suggested that research comparing the predicted reading difficulty of materials with adult reading performance be undertaken. (DI)