This book is a guide to the evaluation and development of textbooks that focuses on the research on which they are based to the writing of the text. It also explores research into textbook effectiveness and provides an overview of the research in the field. The chapters are: (1) "Respondents' Opinions"; (2) "Evaluation of Textbooks by Experiments"; (3) "Analysis of Textbooks"; (4) "Readability Formulae"; (5) "Use of Computers in Textbook Writing and Analysis"; (6) "Suggestions for Comprehensive Writing"; (7) "Criteria for the Optimal Readability of a Text"; (8) "Interest a Text Can Offer"; (9) "Illustrations in Textbooks"; and (10) "Value Forming Aspects of Textbooks." Three appendixes contain information on the validity of methods for textbook analysis, readability formulae, and formulae for predicting text interest. (Contains 58 tables, 21 figures, and 578 references.) (SLD)