“My host, GitHub’s CEO, Chris Wanstrath, began by telling me how the “Git” got into GitHub. Git, he explained, is a “distributed version control system” that was invented in 2005 by Linus Torvalds, one of the great and somewhat unsung innovators of our time. Torvalds is the open-source evangelist who created Linux, the first open-source operating system that competed head-to-head with Microsoft Windows. Torvalds’s Git program allowed a team of coders to work together, all using the same files, by letting each programmer build on top of, or alongside, the work of others, while also allowing each to see who made what changes—and to save them, undo them, improve them, and experiment with them.”