Computer Science: Concepts & Explorations (3rd edition) is a free, interactive textbook for learning about and exploring computer science. It introduces you to key concepts in computing, such as how the Internet and World Wide Web work, what is computational thinking, and how computers are impacting society (both good and bad). It also builds experience with programming and problem-solving through the development of interactive Web pages (coded in HTML and JavaScript).

• FOCUSED: The text focuses on key concepts and skills that are relevant to everyone in the computing age. Chapters are brief yet informative, intended to introduce you to important ideas and skills without overwhelming you.
• FLEXIBLE: It is divided into two sections, Concepts and Explorations. The Concept chapters focus on understanding computers, the Internet and Web, computational thinking, and the impacts of computing. Exploration chapters focus on developing skills needed to design and implement interactive Web pages. For a balanced perspective, it is recommended that these chapters be interleaved (C1, X1, C2, X2, ...). However, you might choose a different ordering to fit your interests.
• INTERACTIVE: Chapters integrate activities to keep you engaged and to encourage reflection while reading. Concept chapters include questions (with answers) at the end of each section, so that you can test your understanding before moving forward. Exploration chapters provide live examples, which you can visualize at the click of a button. Exercises encourage you to modify provided examples and practice the skills you are learning. Many chapters contain hands-on simulations for bringing concepts to life.
• WEB-CENTERED: The World Wide Web is a recurring focus throughout the text, which helps connect the material to an environment you are already familiar with. Learning about and learning to develop Web pages in a Web-based text is a natural.
• FREE: The material in this text has been developed over two decades and been tested in classrooms across the world. It's now freely available to you via the Web.

David Reed is a Professor of Computer Science and Chair of the Department of Computer Science, Design & Journalism at Creighton University. His primary interests are in programming languages and computer science education, where he has published extensively on topics such as apprentice-based learning, Web-based programming, and innovative instructional methods in introductory computer science. He authored the introductory text, A Balanced Introduction to Computer Science, which was published by Pearson in three editions.