Reader theodp writes: Thanks to software, Bill and Melinda Gates report in their 2019 Annual Letter, textbooks are becoming obsolete. Bill writes: “I read more than my share of textbooks. But it’s a pretty limited way to learn something. Even the best text can’t figure out which concepts you understand and which ones you need more help with. It certainly can’t tell your teacher how well you grasped last night’s assigned reading. But now, thanks to software, the standalone textbook is becoming a thing of the past” (if so, it’ll be a 60-year overnight success!). The Gates are putting their money where their mouths are — their education investments include look-Ma-no-textbooks Khan Academy and Code.org. Code.org, whose AP Computer Science Principles course for high schools “does not require or follow a textbook”, boasted in its just-released Annual Report that 38% of all AP CS exam takers in 2018 came from “Code.org Computer Science Principles classrooms,” adding that it had spent $24.2 million of its donors’ money on curriculum and its Code Studio learning platform (30,300 hours of coursework), another $46.7 million to prepare 87,000 new K-12 CS teachers, $12.4 million on Marketing, and $6.9 million on Government Affairs. So, do we still need textbooks?