Edible Forest Gardens (Books 1 & 2), by Dave Jacke with Eric Toensmeier
What is most remarkable about this exhaustive and practical course in temperate climate (zones 4-7) permaculture is that only about 40 of its over 1000 pages are about the work of planting and maintaining an "edible forest garden" ("a perennial polyculture of multipurpose [native] plants"); the rest is understanding what to plant, when, and why. The whole idea of these gardens is to enable you to harvest an abundance of varied foodstuffs with almost no maintenance.
The theory takes up the whole first volume and needs every page. The challenge, you see, is that even what we might perceive as 'wilderness' is in fact nothing of the sort. Humans, right back to First Nations thousands of years ago, have utterly altered the vegetation that now looks so wild and 'natural'. On top of that, climate change has, since the ice ages, been continuously changing what grows where.
In order to allow nature to provide you, effortlessly year after year, a harvest of abundance, you first need to discover what naturally grew and what naturally will grow where you live. You need to study the botanical history of your home. Then, since it cannot be quickly 'restored' to natural, sustainable state (succession goes through many long intermediary stages and can take centuries to achieve equilibrium), you need to be smart enough to plan for a 20-30 year 'hurry-up succession' that will chivy the process along. You have to plant in stages, knowing that early stages are just preparing the soil, the ecosystem and the ground cover and canopy for later stages, and that some of the first things you plant won't be around at the end of the succession at all if you've done your job right. This takes serious knowledge and study, a lot of patience and relearning what our ancestors learned as a matter of course. It's in many ways a course in what Derrick Jensen has called "listening to the land".
There probably isn't anything you could learn that would be more important, for your soul, for your community, for your resilience in the coming age of climate change and other disasters that will require us all to become much more self-sufficient than we are today. Start now, and when cascading economic, social and ecological catastrophes hit us in the 2030s and bring existing food production and other systems to their knees, you'll be ready to gather the fruits of your labour.