Indispensable Permaculture Books?

Besides Gaia's Garden, which I've already read?

I know there's no substitute to going out in your own yard and doing it, which I am starting to. But I can't be in my garden all day, and a beginner needs all the help she can get. Which permaculture books have you read that you found most valuable? Feel free to include books related to permaculture.

I'm guessing Sepp Holzer's Permaculture will be included on a lot of people's lists.

The Designers Manual by Bill Mollison.

"Rainwater Harvesting for Drylands" by Brad Lancaster, especially Volume 2.

Toensmeier's "Perennial Vegetables" is quite good to get people thinking about moving away from annuals, and it has a decent coverage of about 100 perennial vegetables.
http://perennialvegetables.org/about/

Jacke's "Edible Forest Gardens" is a thick, 2 volume work that several friends rave about (my copy is coming soon).
http://www.edibleforestgardens.com/

Fukuoka's One Straw Revolution will get you into all kinds of trouble
Look for agroforestry textbooks.

http://www.soilandhealth.org/

Books are great but do not forget all the amazing videos online at youtube and such. Permaculture DVD’s are great for inspiration, visuals that books can’t give, plus tons of info too.

As to books I just now thought that I would tell people to read in this order:

Tree Crops: A Permanent Agriculture
One Straw Revolution

Then either:

Intro to Permaculture (for broad scale properties)
Gaia’s Garden 2nd edition (for urban to ¼ acre)

Teaming with Microbes is good.
Pat Colby for natural/biological farming
Acres USA and Stockman grassfarmer mags: I don't have animals, but they both have loads of info about raising healthy stock and pasture.
There's more in here than I'm ever likely to read, and it's legit:
http://www.soilandhealth.org/

I have found the new Sepp book to be, for my money, the best permaculture book besides A Designers Manuel.
Edible Forest Gardens are needed for their Appendices. So thankful that we have those, thank you Dave Jackie!
and thank you Paul Wheaton for all the FREE information and material!

Sepp Holzter for Peace Prize! 

Thank you for your suggestions, everyone! A lot of your suggestions are books I was already considering getting my hands on. I was feeling a bit wishy washy about Fukuoka's book, but at your recommendation I think that will be one of the next ones on my list. I don't have the money for Mollison's or Jacke's books right now, though they are on my long term list, as is Sepp Holzer's book.

Are there any permaculture books that you've found particularly useful for small spaces? I live in the city. I'm considering either "Food Not Lawns" or "The Edible Front Yard." Can anyone weigh in on those two?