PS. The MIT Press based book by Harold Abelson and Gerald Jay Sussman with Julie Sussman, foreword by Alan J. Perlis is CC-BY-SA-4.0 and available in 2nd editio

PS. The MIT Press based book by Harold Abelson and Gerald Jay Sussman with Julie Sussman, foreword by Alan J. Perlis is CC-BY-SA-4.0 and available in 2nd edition as PDF here: https://web.mit.edu/alexmv/6.037/sicp.pdf https://web.mit.edu/alexmv/6.037/sicp.pdf