I am not sure if anyone has mentioned the following matter either in this thread or elsewhere on Scubaboard.
Anyway, I recently finished the Science of Diving (SOD) online @ Salty Endeavors in Cozumel. A few days ago, I was looking at my account via the SSI website and found that a PDF book of the SOD online learning material is available for download.
This was found by logging in the SSI site, clicking the 'Services' menu at the top of the page, selecting the 'Download Area' sub-menu and then searching through the list of documents on the 'Download Area' page.