The present study aimed at recognizing the extent to which the guidance included in an , Omani EFL Teacher's Book is educative to EFL teachers in Basic Education Schools in . Oman. It also aimed at exploring and investigating the perceptions that are conceived by the EFL teachers in Basic Education Schools in Oman of the degree to which the Omani EFL Teacher's Books are educative to them and the degree to which they actually use the guidance provided in the Omani EFL Teacher's Books. Two research instruments were used in the present study. First, a content analysis tool was developed and implemented to analyze the guidance included within lessons and the guidance included in the Introduction of the Omani EFL Teacher's Book in question. For this purpose, the researcher analyzed the guidance included in the EFL Teacher's Book of Grade 10 B of Basic Education using the content analysis instrument in order to answer the first question of the present study. The analysis of the guidance included in the Omani EFL Teacher's Book consisted of functional analysis and thematic analysis. That is, the guidance was analyzed into a set of operationally identified and defined functional moves and functional macro categories. In addition, the guidance provided ; Book was further analyzed into certain specific thematic categories. Second, to investigate EFL teachers' perceptions and use of the Omani EFL Teacher's Book, a questionnaire was administered on the sample of the present study in order to answer the second research question. The data collected by means of the content analysis system were qualitatively analyzed. Initially, the researcher displayed the percentages of the frequency of each functional move and each thematic category. Next, the researcher interpreted the analyzed data by discussing the salient distinguishing characteristics of each functional move and each thematic category in terms of both form and meaning. Besides, the researcher made certain claims on the basis of her interpretation of the analyzed guidance. Then, the researcher illustrated and supported her interpretations by presenting examples of those categories from the analyzed guidance. Furthermore, the researcher attempted to identify the degree to which the exploratory functional moves that represent features of educative curriculum materials are actually embedded in the guidance included in the Omani EFL Teacher's Book With regards to the data collected by means of the questionnaire, they were quantitatively analyzed, using descriptive statistics, i.e., Means and Standard Deviations. Furthermore, the researcher used the independent samples T-test and Analysis of Variance (One Way ANOVA) to detect any statistically significant differences in teachers' perceptions and use of the Teacher's Book that can be attributed to differences in their years of teaching experience. The population of the study consisted of all EFL teachers in Basic Education schools in Oman. They were 3669 teachers. Concerning the sample of the present study, it consisted of 649 teachers from four educational reigons; Al-Buraimi, Al Dhahirah, Al Batinah North and Al Batinah South. More specifically, the sample comprised about 18% of the whole population. With respect to the teaching experience of the subjects, it ranged from less than one year to more than twenty years. The following are the main findings of the present study: • The prescriptive functional category seems to be more frequent and more detailed than the exploratory functional category in the guidance included in the analyzed Omani EFL Teacher's Book. The guidance included in the Teacher's Book may need to be supported with additional themes that address and enhance teachers' Pedagogical Content Knowledge, teachers' learning and professional development, Overall, a variety of educative features and themes are actually embedded in the guidance provided in the Omani EFL Teacher's Book especially in the Introduction of the Book, but these exploratory elements may require to be expanded by being made more detailed, more specific, much more frequent, more: omprehensive and more coherent throughout the lessons and units of the course. : They also may need to be further exemplified and clearly illustrated. Omani EFL Teacher's Books seem to be of a quite high usefulness for teaching the language courses textbooks as perceived by EFL teachers in Basic Education schools in Oman. EFL teachers in Basic Education schools in Oman tend to use the guidance included in the Omani EFL Teacher's Books moderately or satisfactorily, but not excessively. That is, teachers' actual usage of the guidance included in the Omani EFL Teacher's Books seems to be far less than its perceived usefulness. EFL teachers in Basic Education schools in Oman generally perceive that the Omani EFL Teacher's Book is moderately useful for their professional development. There were not any statistically significant differences in teachers' perceptions and use of the Teacher's Book that can be attributed to differences in their years of teaching experience. In the light of the findings of the present study, the researcher suggested some recommendations for EFL material designers, EFL Teacher Education and EFL in service teacher training as well as EFL teachers. Finally, the researcher presented some suggestions for further research.