Long time readers know of my love affair with Abelson & Sussman's Structure and Interpretation of Computer Programs. I regard it as certainly one of the best and arguably the best computer science books ever written. MIT Press, in a gesture of public service long before such things were common, made the book publicly available and, along with the video lectures that Abelson and Sussman gave at HP, it serves as an invaluable resource to anyone with the wit and energy to take advantage of it.
Now, thanks to the efforts of Lytha Ayth and Neil Van Dyke, a new PDF of the book has been derived from the original HTML sources that MIT Press made available. Take a look at this announcement from the SICP site to see what a difference real typesetting makes. For a concrete example of the difference, take a look at Exercise 1.2 from the original HTML source and the new PDF version. The HTML source is unreadable while the PDF is perfect.
It's really great that this wonderful resource continues to be made available in better and better formats. We all owe those who brought it to us a huge load of thanks.