Peter Harper is Head of Research and Innovation at the Centre for Alternative Technology in Wales, UK, where he has worked for over 20 years (www.cat.org.uk). He is also a visiting lecturer at universities and other institutions around the world. His interests have ranged widely, including energy policy, sustainable lifestyles, ecovillages, alternative sanitation, landscape design, organic horticulture, and composting (with which he is mildly obsessed – don’t get him started). His publications include Radical Technology (1976) an influential early textbook of technical alternatives, The Natural Garden Book (1994) and Lifting the Lid (2000) on low-impact sanitation systems. His colleagues regard him as a loose cannon often at odds with Green orthodoxy. His friends think of him as an agreeable nerd.