Textbooks could play a crucial role in shaping the readers’ social identity (e.g. van Leeuwen, 1996). Textbooks may be used by curriculum developers to inculcate certain values onto the learners. They may also be used by the society in general and the educational establishments in particular to impose certain normative identities on individual (social) citizens and class attendants. To examine the validity of this claim, the present book includes the findings of a study designed to analyze textbooks, as the subject matter of the curriculum used in educational institutions. It examines the function of language as a social practice in skill-based textbooks used to teach English as a foreign language in schools and universities in Iran. The main tenet of this book is to identify the type, nature and percentage of the social actors used in textbooks. According to the analysis, discursive structures such as deletion, role allocation and substitutions present a clear picture of the ways social actors have been represented in the textbooks under study.