Barbara Ericson is a senior research scientist and a Human-Centered Computing PhD student. She has been involved in the creation of several interactive ebooks using the Runestone Interactive platform. She contributed practice questions to the “How to Think Like a Computer Scientist: Interactive Edition” ebook, was one of the primary authors of the student and teacher versions of the Computer Science Principles ebooks, and was the primary author of the Java Review ebook. She also led the development of several new features for the ebooks, such as audio tours of code and mixed up code problems, which are also called Parsons problems. Parsons problems break correct code into code blocks that are mixed up and the learner must place the blocks into the correct order.