Through globalization, English language expansion is gaining momentum more than ever before. One can hardly discover an education system worldwide where English language finds no prominent place as it is viewed a desirable asset and also the single most important avenue to professional career success. Nevertheless, the spread of English has recently raised concerns and mixed feelings of hope and fear. It is assumed that the unilateral propagation of the language is hegemonically sweeping aside all other cultures and languages. To unravel the cultural orientations of English textbooks, the present book provides a practical analysis of two series of books, i.e., Interchange Series which have come to be widely taught and learned across the globe and the secondary school English textbooks developed and used In Iran. The book presents a quantitative and qualitative picture of the contents of the books, revealing in which direction they are culturally skewed.