We did a pre-launch at Okta's conference in Las Vegas in August, and it's taken a bit longer to sort out the details of actually listing it for sale. It's available for purchase right now at the website, and will be visible on Amazon.com in 6-8 weeks.
Next I'm working out the logistics of publishing an ePub/Kindle version, which it turns out is not just pushing the "ebook" button. This has been a fascinating process to learn about!
I've done conversions for .epub/.mobi before and have some infrastructure for it. Let me know if you want/need help.
Thanks! I actually just finished the technical side of it this morning. Turns out it was more about doing things like writing conditional text for things like "the figure above" instead of "figure 1.4" since the figure numbering happened in the HTML->PDF toolchain step. I think I have a finished epub and mobi file now, so I just have to figure out the distribution step through Lulu.com now. (It's also made slightly complicated by the rev share agreement, so I can't just go wild with distribution or direct online sales of it.)