This book is a synthesis of the complex interdependencies between user interface design of digital screen and learning process. It is analyzed the impact of digital revolution on learning, phases of digital textbooks use and development; specific features of educational system & learning environment; psycho-pedagogical characteristics of XXI students; user interface design topology; user interface design features of digital textbooks in accordance with human thinking paradigms; critical thinking of user interfaces and content (linear, systems, global and metasystems design approach). One special chapter describes innovative organizational forms of learning with digital textbooks. Metasystems learning design of digital textbooks will be of particular interest to the readers because this is an innovative approach of learning design, which proved the experimental data of the instructional dynamic and flexible strategy. It proved the practical application of didactical model of digital textbooks for chemistry and mathematics. The main benefits for reader refers on understanding the applicability of metasystems learning design for digital textbook use and development, in particular for STEM education. It takes more than analysis to help readers overcome the impact of user interface design of digital textbook on learning outcomes.