All you have to do is enter the promo code OKTOBERFEST305 when you check out. All three volumes are available, Major, Dominant and Minor 7 chords.
And there are plenty of other bass books up there as well, some are really cheap, some are older, some are obscure and they seem cover the range of experience, from rank beginner to more complex. Plus the coupon code is good for any book you buy on Lulu.com until the 23rd at midnight. Of course, I have some pretty strong opinions about which ones you should buy.