Penelitian ini bertujuan untuk menghasilkan e-book  interaktif pada materi virus untuk melatihkan keterampilan berpikir kritis siswa kelas X SMA yang dinyatakan layak dari segi teoretis maupun empiris. Kelayakan teoretis ditinjau berdasarkan validasi. Kelayakan empiris ditinjau berdasarkan keterbacaan, keterlaksanaan, ketercapaian keterampilan berpikir kritis dan angket respon siswa. Model pengembangan yang digunakan adalah 4D (define, design, develop dan disseminate) namun hanya sampai pada tahap develop yang dilakukan di Laboratorium Pembelajaran Pusat Kajian MIPA dan Pembelajaran Gedung IsDB, Fakultas Matematika dan Ilmu Pengetahuan Alam, Universitas Negeri Surabaya pada bulan September - November 2019. Teknik pengambilan data dilakukan dengan metode validasi, pengamatan, keterbacaan dan angket siswa. Analisis data dilakukan secara kualitatif. E-book interaktif yang telah dikembangkan diujicobakan secara terbatas pada 20 siswa kelas X SMA Negeri 1 Driyorejo pada bulan Desember 2018. Hasil validasi oleh pakar diperoleh skor rata-rata keseluruhan sebesar 3,84 dan dinyatakan sangat layak. Kelayakan empiris berdasarkan keterbacaan memperoleh hasil level kelas 10 yangmenunjukkan e-book sesuai digunakan siswa kelas X SMA.  Keterlaksanaan e-book interaktif pada materi virus untuk melatihkan keterampilan berpikir kritis siswa menunjukkan vii kepraktisan 94,45% dengan kategori sangat praktis. Ketercapaian indikator berpikir kritis siswa yang dilatihkan memperoleh skor rata-rata keseluruhan sebesar 81,31% dengan kategori sangat baik. Sedangkan angket respon 20 siswa  menunjukkan 97,87% dengan kategori sangat positif.

The purpose of the research are to produce an interactive e-book on virus material to train critical thinking skills of student senior high school grade X who are stated to be valid in both theoretical and empirical terms. The theoretical feasibility was reviewed based on validation. The empirical feasibility was reviewed based on readability, implementation, acritical thinking achievement and questionnaire responses of students. The research was conducted based on 4D model (define, design, develop and disseminate) but only that reached the develop stage in the Learning Laboratory for MIPA Study Center and IsDBBuilding Learning, Faculty of Mathematics and Natural Sciences, Surabaya State University in September - November 2019. Data collection technique used validation, observation, readability and student questionnaire. Data analysis was done qualitatively.Interactive e-book has been tested on a limited basis for 20 students grade X of Senior High School 1 Driyorejo in December 2018. The results of the validation by experts obtained an overall average score of 3.84 stated to be very feasible. Empirical feasibility based on readability obtained the result of class 10 levels wich showed e-book suitable for used by student senior high school grade X. The implementation of interactive e-books on virus material to train critical thinking skills showed practicality with a percentage of 94%. The achievement of critical thinking indicators of students who were trained to obtain an overall average score of 81,31% with  very good category. While the questionnaire responses of 20 students showed 97.87% gave positive responses.