John Williams is at the forefront of Australia's leading soil physicist/hydrologists, demonstrated by the positions he holds and more than 100 published papers. His early work in soil hydrologic properties provided the foundation for much of his later work on sustainable agricuture. Williams has been a leading advocate for ecologically sustainable development of agriculture. He has actively engaged in the public debate around sustainable development as a foundation member of the Wentworth Group. He continues to be actively and centrally involved in promoting sustainable management both in government policy and in the field, as Comissioner of the NSW Natural Resources Comission.