When it comes to small-scale organic farming, Eliot Coleman's name keeps coming up. He's written a couple of books. The new classic is The New Organic Grower: A Master's Manual of Tools and Techniques for the Home and Market Gardener (Chelsea Green Publishing). The Revised Expanded Second Edition (1995) is the one to get. It's a must-have!
Coleman's other book, Four-Season Harvest (1999; Chelsea Green), is also really good. It explains his movable greenhouse system, and as the title suggests, about half covers season extension and winter growing.