zyBooks are animated interactive textbook replacements built from scratch for the web. zyBooks have minimal text and instead consist of question sets, animations, interactive tools, and auto-graded homework, so students can learn by doing. The zyBooks platform allows instructors to customize their zyBook and to monitor student participation and performance. zyBooks have been used in over 600 universities by over 250,000 students. We offer titles for introductory and advanced computer science and engineering classes, as well as other STEM disciplines. User studies have consistently shown improved student grades, thus supporting the company's mission to help more students graduate, especially in the STEM disciplines.