The purpose of this book is to introduce the research on readability, defined here as reading ease. The first part of the book covers how people read. A series of national literacy surveys show that the average person in the U.S. and most other countries are adults of limited reading skills. For example, the average adult in the U.S. reads at the 9th-grade level, with nearly half reading below that level. The second part of this work covers the efforts made to match texts with readers. The research shows that more readable texts increase comprehension, retention, reading speed, and persistence. Other studies show how factors in both the reader and the text contribute to reading ease. Finally, the work follows the development of the readability formulas and the controversies that surrounded them. George Klare's Readability Ranking Test is appended. An index is included. (Contains 14 figures and 9 tables.)