All respect to both Toensmeier and Jacke's work, but I wouldn't classify these books as essential as much as theory tomes for the nerds. If people want to get into forest gardening or agroforestry, there are examples of much more accessible and useful literature. For the temperate climate, Martin Crawford's books are still the best around as introductions. "Creating a Forest Garden" specifically and then the thematic species-oriented books on perennial vegetables, trees and bushes (each has a book).
The reason I wouldn't recommend Toensmeier and Jacke's two volumes for people starting out is that people often get stuck with principles, ideas and theories instead of practical advice to go ahead and grow some of the crops. I've seen this again and again with urbanites obsessing over which theory applies to this or that hypothetical situation, but having almost no growing experience. For the effort it takes to plow through hundreds of pages of dense ecological theory (and to it's defense, it's great as theory), the payoff is not worth it for beginners.http://libgen.li/search.php?req=creating+a+forest+garden&