Development of Teaching Materials in the Form of Electronic Books Integratedwith Generic Science Skills in Chemical Equilibrium i Selection of teaching materials is an important part of learning, therefore teachers can develop appropriate teaching materials to increase the effectiveness of the learning process. Thus, the research was conducted to develop teaching materials in the form of electronic books integrated with Generic Science Skills (KGS) to improve students' high level thinking skills in chemical equilibrium material in Class XI Senior High School at Laksamana Martadinata Private High School Medan through research and development (R&D) the 4D model (Define, Design, Development, and Disseminate). The development of teaching materials starts from (1) book analysis (four books were analysed) and concept analysis, (2) design of teaching materials, (3) standardisation of teaching materials using a modified BSNP assessment questionnaire, (4) revision and development of teaching materials, and (5) field testing of teaching materials and final revision. The teaching materials consist of features such as "To Remember", "Basic Understanding", "Chemical Concepts" and several pictures that serve as supplements to enhance the KGS, and features that increase knowledge and attract students' interest in the learning material, such as "Chemical Info", "Chemical News" and "Chemical Figures". In the teaching materials, there are "Sample Questions" and " Practice" to further train students' understanding. Based on the results of standardisation by material experts and media experts, the teaching materials go through the revision stage to produce teaching materials that are very suitable for use in learning. Then, field tests were conducted to obtain the reactions of teachers and students as users of the teaching materials, and the results showed that the teaching materials were very well used as learning resources and very interesting for students.