Abstract: For electronic textbooks designers, learning efficiency is a major challenge. Cognitive load theory (Sweller, Ayres & Kalyuga, 2011) and multimedia learning theory (Mayer, 2014) have identified several effects which can be used for the improvement learning materials. We used these effects to provide general recommendations for textbooks designers; working for a major French publisher. However, to improve digital textbooks and provide specific recommendations, we conducted a qualitative study among secondary schools. The main questions raised were as follows: how student and teacher use digital textbooks in class, what kind of difficulties they face and how they manage these. The results show “use” and “non-use” factors that publishers may be interested to take into consideration