I hate the Dummies series on principle, but this had some useful information. Most of the projects Browning uses as examples are a lot larger in scope than the grant I'm currently working on, but much of the information was transferrable, and I'll be referring back to this book as I work my way through the application.

A great resource/reference manual for any grant professional from the newbie to the seasoned professional. As a grant professional, I highly recommend this book and wish I had read it when I was first starting out.

Probably very useful for non-profits but less helpful in academia. I suspect the 2005 version is out of date by now in a lot of ways, but it still had some good tips.

Helpful, generic introduction to grant writing. Covers a very broad swathe so a good intro but not where you'll want to camp out long term. I appreciate some of the general writing advice, though, such as action verb use.
Incidentally, this is only about 50% helpful if your non-profit doesn't look for government grants.