Computer science studies how to describe, predict properties of, and efficiently implement information processes. This book introduces the most important ideas in computing using the Scheme and Python programming languages. It focuses on how to describe information processes by defining procedures, how to analyze the costs required to carry out a procedure, and the fundamental limits of what can and cannot be computed mechanically.

David Evans is a Professor of Computer Science at the University of Virginia where he leads research on security and privacy and teaches courses on operating systems, introductory computer science, and applications of cryptography. His Udacity cs101 course is the world's largest open course. According to Prospect Magazine, "Evans is the kind of nerdy savant whose gap-tooth smile and Monty Python humour attract a cult following on campus." But, Zeit writes, "Steht »Correct!« da, freue ich mich, fast, als hätte mir Professor Evans persönlich gratuliert."