I'm a big fan of The Wild Wisdom of Weeds by Katrina Blair - with a few caveats. This is a subject that I feel passionately about, because Americans devote an absurd amount of resources to removing helpful, edible, and medicinal plants (a.k.a. weeds) from our useless monocultures (a.k.a. lawns) every year. And then we use more resources to grow, harvest, process, transport, and buy other foods - in some cases the very same weeds we want to kill in our lawns (i.e. dandelion greens). Therefore, this book is a breath of fresh air because it lends some much needed perspective to the usefulness of the weeds we overlook and waste.
Blair establishes herself as an expert on the subject early in the text, telling how she spent an entire summer living off of wild plants. The book is organized around 13 extremely common weeds that you can find no matter where you live in the world, give or take Antarctica: dandelion, mallow, purslane, plantain, thistle, amaranth, dock, mustard, grass, chickweed, clover, lambsquarter, and knotweed. I've personally found all 13 here in Wisconsin, and all but two in San Diego (although it's possible I just wasn't looking hard enough).
For each weed, Blair tells how to recognize it, why it's useful, and what to do with it. She provides recipes too.
This is where the caveats come in. It appears Blair is a raw vegan, or at least her recipes are. This type of cuisine can be delicious, but if you are not a raw vegan yourself it can be limiting. You might personally find it more useful to have a recipe for dandelion pesto with dairy cheese in it and instructions to cook it, rather than recipes for raw foods, which often call for dehydrating foods and never bringing temperatures above 114F or so. On the other hand, if you ARE a raw vegan or you enjoy that type of cuisine, then this book is for you.
My other caveat is that Blair is a spiritual person, and her spirituality comes through in her writing. If that's for you - and a lot of people will find it very appealing - then that's great. If it isn't for you, I fear it might turn some people off. That would be a shame too, because there are not too many books out there covering such a crucial topic, and this one is full of valuable info.
My recommendation is to get the book, and if you aren't into Blair's flavor of spirituality and raw veganism, just let that stuff go. Read the book, and learn what you can from it. You'll almost certainly find a wealth of healthy food growing in your own lawn. Then look online for non-raw, non-vegan recipes using these delicious plants.