Structure and Interpretation of Computer Programs (1996) [pdf]
I'm glad about SICP being promoted and accessible to people around the world.<p>Maybe 20 years ago, the authors put the full text for their textbook on the Web, as HTML.  This made it more accessible to people, and set an early precedent for freely-available top textbooks on the Web (even though they presumably could've made more money by only selling print copies).<p>Then, since not all students' computers could run a Web browser, Lytha Ayth manually converted the HTML to Texinfo, with ASCII art of all the figures.<p>If one has the means to buy the printed book, doing so would seem like a nice gesture, in response to the authors' and publisher's generous sharing and example-setting.