Despite the effects of new technologies, textbooks will certainly continue to play an important role in the process of language teaching and learning. The purpose of this study was to evaluate the English textbook which is taught in Iranian first grade high schools. For this purpose, the weaknesses and strengths of the English textbook are explained using 13 criteria which have been drawn on various checklists. The study was carried out at four schools of Tabriz, Iran. The data were obtained from a total of 126 language students, both female and male. It was collected through a questionnaire with 34 close-ended questions which were related to the seven sections of the book including the layout or physical make-up, vocabulary, topics and content, grammar points and exercises, language skills, pronunciation practice, language function, and social and cultural activities. Quantitative data were analyzed via SPSS. Meanwhile, qualitative data which were obtained through interviews with teachers and students were analyzed interpretatively. The results show that this book cannot meet the Iranian students' and teachers' needs and wants. It can be concluded that the English book 1 is grammar-based. So, the writers of the book had better modify it by employing more communicative tasks in order to motivation both teachers and students.