There seem to be several reasons for no book covering bimac (or octo) behavior. First of all, most scientific studies are narrow, covering only one specific behavior and there aren't many of those published. The results are usually journal articles. Some are posted on the web, and some are not.
Like the Cephalopod Behavior book, they may cover squid and cuttlefish in addition to octos, so the octo content is not so large. Most of us find that the Ceph Behavior book approach is not what we're looking for.
But, on the other hand, it's not easy to track and document behavior in a controlled way and we need many examples to even begin to draw conclusions. Each person can do help by observing and reporting about his octopus or maybe even running some simple behavioral experiments.
I hope we have a beginning of a better record of bimac behavior from what is reported here on TONMO.com under the Journals and Photos. As far as behavior goes, I think we've just scratched the surface and need many more examples before we can draw conclusions, given the variety in the behavior shown so far.