Based on the findings from reviewing 32 textbooks in the past four years for Taiwan's Ministry of Education, we have identified common problems in the reviewed textbooks and analyzed their inadequacies. Typical problems include the Wintel bias, too much coverage of software application tools and too little of computer science concepts, too many technical terms, meaningless analogies and examples, lack of supplementary materials, and inadequate treatment of programming-related content. The discussion about each problem is substantiated with examples, and suggestions are made on possible improvement. This analysis should help textbook writers avoid undesirable elements in their books and help high school computer teachers select higher quality books for their students.