This book tries to be everything for everyone, and as a result ends up not very helpful for anyone. It tries to deal with all the various differences in proposal formats between different fields and different funding agencies, so all of its advice is tempered with "except sometimes" and "check with your own university" and "not necessarily".
Also, there's a sort of saccharine idealism throughout the book, in which the authors speak as though THE ONLY THING that decides whether a proposal is accepted is its scientific quality. Clearly this is a major factor; I'd like to think it's the biggest factor. But equally clearly, there are a lot of good studies that don't get funded and a lot of bad studies that do. One way we could actually improve this situation is by teaching people with good ideas how to make those ideas appealing to funding agencies. As Aristotle said, being persuasive does not make you right, but those who are right have an obligation to be persuasive.
For someone like me who already knows the basics of writing science proposals and is looking for really detailed advice to get past the slush pile, this book isn't helpful. It might be useful to someone who didn't even know where to start.