Hi Brian
I dont think I've ever used the actual book itself effectively. I feel the listings are never in the section you think they should be.
I would tend to either use Yell.com , Thomsons Local website or a search engine (i.e Google)
My view is that if a company doesn't (in this day and age) have a good informative user friendly website or can be fouund on T'internet they're behind the times and maybe not moving with customer demands enough.