Geoff Lawton dvd, Permaculture soils is a fascinating insight into the billions of living organisms who's activity creates living soil. Any gardeners will find this invaluable and worth the money imo.
It's full of great ideas like how to make compost that doesn't lose any of it's bulk in 18 days (yes, really) and your increased crops will pay for it in no time.
We keep watching ours over again.
