+1 vote for Kourik's book. I'm just reading it now. Permaculture isn't mentioned much, but that's what it is. Of course, I think the word was trademarked or something back then.
This. ^ I can't recommend this book enough, especially for the urban permaculturist. Kourik's other stuff is wonderful and accessable as well. Some of what he's written makes it seem to me that trademark isn't the issue...he's deliberately avoiding the word "permaculture"...
I was surprised at first to see
Nausicaa of the Valley of Wind on here, I always thought of it primarily as a brilliant humanist work, but don't permaculture and humanism go hand in hand? Anyway, I can second the recommendation of the manga. Well, if we're nominating works of philosophy I say check out Joseph Campbell's
Myths to Live By. Also, or course, Wendell Berry's
The Unsettling of America, especially the chapter "Where are the People?". Both books are dated now, but still highly relevant.
I just finished reading Carol Depp's
Breed Your Own Vegetable Varieties and enjoyed it thoroughly. Even if you have no designs of intentionally breeding your own varieties this is a good book to check out. As she points out, as soon as you start saving your own seeds, you are engaging in selection, and have become a plant breeder of the old school.

The book also encourages a lively sense of experimentation and observation in the garden and farm. In addition, she gives good advice on obtaining germplasm, with lists of sources for both annual and perennial crops, and advice on obtaining stock from the USDA Germplasm system, which in my opinion is a vastly overlooked source (no doubt because people are astonished that the USDA actually does something useful). On top of all it's other virtues, this book is a good seed saving reference. It now occupies a place of honor on my shelf next to
Seed to Seed.
I also re-read
Plants, Man, and Life and
Farmers of Fourty Centuries recently. These books are old too, I guess they are more the ground permaculture sprang from than specifically permacultural readings. Both are excellent, I particularly enjoy the former for elaborating on the theories of how we domesticated plants, and they domesticated us... You may recognize a food forest being described in chapter 13.

The latter is likewise fascinating but I was a bit depressed to see someone writing in 1908 on the foolishness of westerners refusing to utilize humanure and realizing that nothing has changed on that front in 100 years.