Knowledge as a sole product of education is no longer a desirable outcome of the teaching process. The governments and international institutions in today’s global world call for national curricula whose aim is to educate independent, yet responsible citizens that are able to think critically and through their rational actions contribute to the well-being of the whole society. One of the ways of achieving this goal is incorporating an intentional development of higher-order thinking skills into the educational process via the use of teaching materials with cognitively demanding content. This diploma thesis seeks to analyse two selected textbooks of the CEFR level C1 in terms of their application of the Revised Bloom’s Taxonomy and assess the extent to which they engage students in tasks and activities necessitating the employment of higher-order thinking skills. In its theoretical part, the thesis clarifies the principles and basic concepts of the taxonomies of educational objectives, focusing on the cognitive domain, namely the original and revised Bloom’s Taxonomy of Educational Objectives and their interrelation with teaching and learning English as a second language. The practical part specifies methods and aims of the research. Subsequently, it analyses the selected textbooks applying content analyses of the tasks using the Revised Bloom’s Taxonomy as an instrument providing a checklist of criteria against which the textbooks are analysed. It then compares the materials by conducting a comparative analysis, followed by a semi-structured interview in order to obtain the post-use opinions of teachers using the books on the cognitive challenge of the materials. In conclusion, the paper produces the results of the study that can be utilized by educational institutions seeking to select teaching resources for delivering C1 level instruction in their ESL classes.