I tried to read through An Incremental Approach but found that it was really too brief. I had questions that I wanted answered but he was briskly moving on to c

I tried to read through An Incremental Approach but found that it was really too brief. I had questions that I wanted answered but he was briskly moving on to compiling the next Scheme form. I found the first chapter of a longer version from his site, but this seems incomplete. Does anyone know what happened to that? Did it not turn into a book?