This has actually gone public, without any request not to say anything, so I trust it's OK to mention it to anyone who finds themselves here and doesn't know yet.

This is poorly worded enough that I'm not actually sure what you're saying. I have a tentative prediction that you were trying to say something like 'Eliezer has said to some acquaintances and public that the first draft etc.; as he did not request them to maintain the privacy of his statements, I am making it further public since I know many people are interested in the progress of his book.'

packed with hundreds of pages of novel content.

over 500 pages)

Hrm. I would have expected the sequences to have made a good 300 or 400 pages after editing and polishing...

two sub-books

What are sub-books?