This method is calld controlled crying and I know its recommended by most UK HVs. I have to say I really don't know why. I can see how it would work with older children, say 3 and up where there's more to it than sleep. However, with babies I think its horrid and I think that's a view Tracy shared.
I can't honestly understand how it would work with babies who don't have the cognitive powers to work out what you are doing, to them it must seem like they've been abandoned.
Anyway, enough of my spouting. The BW method does not involve leaving the baby, it does involve crying and being very firm about sleeping in their bed. If you would like to know how to do it, I would suggest getting Tracy's third book and reading the sleep interview at the top of the sleep issues forum.