The purpose of this study were to survey scientific research, professional literature, and doctoral dissertations on reading comprehension done from 1948 to 1972, to identify the reading factors believed to affect reading comprehension, to analyze the identified reading factors by studying the major available research and related literature, to identify related findings, and to develop generalizations and conclusions which were used to formulate a construct of reading comprehension. Based on all available research conducted in the past 24 years on factors affecting reading comprehension, the following conclusions were derived: research on vocabulary as a factor affecting reading comprehension was found to be limited, and it was found that intelligence, vocabulary, and reading ability were significantly related; research on sentence structure as a factor affecting reading comprehension revealed that reading comprehension was a function of the similarity of the oral patterns of language structure used in reading materials; research on rate of reading as a factor affecting reading comprehension revealed that the ability to retain verbal information was a function of intellectual ability; and questioning and purpose setting as factors affecting reading comprehension revealed that questions at the end of a passage enhance the retention of prose material. (Author/WR)