Basically, the moon is pushed closer into orbit with the Earth. The book is about a boy and his family trying to survive.
I haven't read the book, but I've read the companion, Life as We Knew It. The science is pretty messed up, and when a fourteen year old can tell it's messed up, you know it's messed up. The ending is also sort of out of the blue, a deux ex machina. But despite that, it's a really good book. The characters are great, showing how desperate people can get, the story is interesting, and it showed me how much I take for granted.
All in all, yes, based on what I know of Susan Beth Pfeffer, I recommend The Dead and the Gone.