Teach Your Own: The John Holt Book Of Homeschooling

A useful introduction to the ideas behind homeschooling (or "unschooling") if a little light on practical examples. The appendices at the end are a treasure trove of useful information and links, even if a lot of it is US-centric. I think this is a good starting point for people interested in learning about what homeschooling is and why people might want to consider it.