There's a link on my site to go on the alerts mailing list :-) It's literally not finished yet. (21,284 words of body text at this moment and I have maybe 5k-10k to add. I was targeting 15k for a quickly dashed-off Kindle short, and I appear to have turned the project into a miniature Sistine chapel.) I have excerpts from the draft up at the site. Which I just moved to http://davidgerard.co.uk/blockchain/ .