From the webpage:
This Gitbook (available here) is a work in progress, converting the MIT classic Structure and Interpretation of Computer Programs to Lisp Flavored Erlang. We are forever indebted to Harold Abelson, Gerald Jay Sussman, and Julie Sussman for their labor of love and intelligence. Needless to say, our gratitude also extends to the MIT press for their generosity in licensing this work as Creative Commons.
This is a huge project, and we can use your help! Got an idea? Found a bug? Let us know!.
Writing, or re-writing if you are transposing a CS classic into another language, is far harder than most people imagine. Probably even more difficult than the original because your range of creativity is bound by the organization and themes of the underlying text.
I may have some cycles to donate to proof reading. Anyone else?