This study investigates how teachers and students assess the textbooks they use in history courses at. the high school level in Turkey. Through a survey questionnaire, teachers and students were asked their perceptions of the textbooks. Then a sub-sample of the teachers and students were interviewed to collect more in-depth data on their assessment of the textbooks. The results indicated that the textbooks assist the teacher in instructional planning and in preparing exams, and help the students deal with the content. However, both teachers and students point to problems in textbooks in terms of their physical aspects, content presentation and organization, language, teaching and learning aids, and their impact on students. The textbooks focus mostly on transmission of knowledge, and they are found ineffective in leading students to read the information with interest and develop an understanding of the content area. They are found ineffective in developing students' thinking skills and positive attitudes toward the subject.