Reading as thinking, the key to reading maturity, flexibility, and efficiency, is dependent upon the reader's purposes and his repertory of reading skills. Instruction should begin with the teacher's evaluation of the reader's functioning skill level, his psychological characteristics, and the nature and quality of his stored information. Skillful reading instruction from the beginning and at all levels contributes to this essential objective--reading as a thinking process. The flexible reader, as a result of his attention to purpose, difficulty of material, complexity of theme, and background knowledge must make adjustments in his reading approaches. Variability in rate does result from this reading-thinking process. Therefore, teachers should present their students with varied reading material, provide exercises in reading for a variety of purposes, and frequently assess progress in developing reading flexibility. References and applications of the reading as thinking concept to the classroom are included. (Author/CL)