Joi Ito · CC BY 2.0

Hal Abelson co-wrote Structure and Interpretation of Computer Programs, the MIT textbook that shaped how a generation of programmers were taught to think about computation, and directed the first implementation of the Logo language for the Apple II, bringing it to personal computers in 1981. He co-founded Creative Commons and the Free Software Foundation and helped launch MIT OpenCourseWare, extending his commitment to open access from software into education. He later led MIT's internal review of its role in the prosecution of Aaron Swartz, which found no legal wrongdoing but recommended the university reconsider its approach.