Ken Webster's popular guide to getting started in ESD is Rethink, refuse reduce... Education for Sustainability in a Changing World.

The publishers are the UK's Field Studies Council. Also published in Georgian, Urdu, Russian and Uzbeck (please contact Ken at Sense & Sustainability if you would like a Russian (print) or Urdu (pdf) copy)

The reworked Indian (English ) Edition is available free here as a pdf. It was edited by the folks at CEE India.