CS50 is Harvard University's introductory course for majors and non-majors alike, a one-semester amalgam of courses generally known as CS1 and CS2. In 2007, we set out to alter the course's style and tone to resonate with those "less comfortable" and "more comfortable" alike, albeit without sacrificing the course's historical rigor. We maintained the course's underlying syllabus but revamped every problem set, providing students not only with more direction but context as well. And we augmented the course's support structure. As of Fall 2016, CS50 is Harvard's largest course with over 700 students, up from 132 in 2006, and those "less comfortable" now compose the course's largest demographic. Since 2015 has CS50 been offered in parallel at Yale University. And CS50 also exists as CS50 AP, an adaptation for high schools that satisfies the College Board's new AP CS Principles curriculum framework.
We present in this talk what we have done and why we have done it. We also look at CS50’s online counterpart, CS50x, Harvard College's first course to be offered on an even larger scale via edX with nearly 1M registrants. And we examine CS50 AP and our vision for secondary-school education.