This is a print companion to the Massive Open Online Course (MOOC), Data Structures: An Active Learning Approach (https://www.edx.org/course/data-structures-an-active-learning-approach), which utilizes the Active Learning approach to instruction, meaning it has various activities embedded throughout to help stimulate your learning and improve your understanding of the materials we will cover. While this print companion contains all STOP and Think questions, which will help you reflect on the material, and all Exercise Breaks, which will test your knowledge and understanding of the concepts discussed, we recommend utilizing the MAIT for all Code Challenges, which will allow you to actually implement some of the algorithms we will cover.