This research paper evolves from and revolves around a prevailing assertion: namely, that is the teaching-learning process has a firm attitudinal footing. Differently stated, the aim of this study is to explore and evaluate the authenticity of the Algerian English textbooks at high school level as they are considered as an important instructional materials and fruitful resources for helping English language learners develop communicative competence. This investigation is tackled by inquiring about the following questions: To what extent are the texts and tasks included in the Algerian secondary school textbooks authentic? And how far does "New Prospects" help English as a foreign language (EFL) learners improve their communicative competence? It should be noted that the targeted population of this study are the Algerian secondary school teachers of English in the region of Mascara of which 35 English language teachers responded to the questionnaire copies in addition to the use of an informal observation as research instruments. The findings of this investigation disclose that the English textbook « New Prospects » that is currently used by third year Algerian high school pupils doesn't offer classroom learners adequate opportunities for learning authentic language. This is due to many reasons such as the choice of one type of English at the expense of another which is more dictated by both political and economical considerations rather than by pedagogical concerns in addition to the lack of an appropriate model because most English adopted versions lack Englishness in addition to the mechanical way in which the tasks presented in the prescribed textbook are tackled and being dealt with. According to the obtained results, the researcher suggested the use of visual aids, Informational Communicative Technologies (ICTs), and some useful communicative tasks as pedagogical recommendations so as to remedy the situation.