I have to say, it is pretty hard to find, if you're not in the loop. I tried Googling various ways before asking directly in this thread, and I could only find it at fotoimpex.de after a few attempts, and didn't turn it up at the Formulary. I also tried searching APUG and couldn't turn up the post stating where the book was available, despite having used the APUG search engine, oh, at least once or twice before.
I had a suspicion it might be at the Formulary, but hunting around their website I couldn't find the books section. Who would have guessed that I should click on "Labware/Bottles" to find books? Until you mentioned in a PM that it would be there and I looked further, I'd just assumed they'd stopped selling books altogether.
So as far as marketing the book goes (and for the past couple of years, the marketing of books has become a significant portion of my job description), I think you're 95% there--you're really active on a number of internet forums, you're doing workshops, and you have all sorts of people interested in what you're doing, and they know who you are and that you have a product to sell. Up to this point, I'd say you have a wildly successful guerilla marketing campaign, that probably doesn't even involve a penny spent on print or internet advertising (or if you or your vendors have bought advertising, I haven't seen it). Your potential customers just don't know, unless they are following very closely, where to send the check to obtain the product.
You have a recognizable name and a recognizable internet handle, so the Formulary would sell more books if they gave you an author bio and made the page accessible to search engines, not to mention making it easier to find books on their website. "Labware/Bottles" indeed!
And it wouldn't hurt to have other ways of buying it, if you don't have an exclusive agreement with the Formulary (and if you do, they should be doing more for you)--Freestyle, Artcraft, GEH if they sell books, and Amazon (if you don't have ideological objections to Amazon) are all reasonable possibilities.