I do keep myself educated on the behaviors and activities of my local bear population. Black bear attacks just don't happen here yet, with the exception of the fatal attack in 1997. That doesn't mean black bears will never attack, but they aren't showing signs of changing, whereas the local griz are getting more aggressive in certain parts of the city. No one book is going to be accurate for every population... general behavior and how you should respond, yes, but not the specifics of an area. I don't know why the black bears in your area have become so dangerous, but I can tell you that the bears here are not that aggressive. There are isolated cases of witnessed black bear stalkings, but it is rare, and usually either involves food (like a nice smelly pack full of yummy bear treats) or curious juvenile bears.
I reiterate... find out about local bear behavior from those who know the local population. They are the best resources for information. Clearly in northern BC the black bear are to be given very wide berth. In most of the US black bears are not interested in humans, just the yummy picnic baskets they carry on their backs. IMHO, all bears are to be respected as the wild animals that they are - you just never know how any individual animal is going to react to human intrusion.
YMMV. Viewer discretion is advised.