Permaculture is a design and maintenance strategy and philosophy centered around preserving and extending natural systems. Though practices of permanent agriculture can be found world-wide dating back millenia, the term was coined and the concepts were developed around 1974 by Bill Molison and David Holmgren in Australia and have since spread globally, being refined and retuned by millions of people who may or may not have taken Permaculture Design Courses (PDC) from other Permaculture Designers and Teachers. Together, Mollison and Holgren wrote the first Permaculture book titled Permaculture One, and since then many books have been written on the subject. In it's most basic form, permaculture consists of a set of three ethics: Earth Care, People Care, and Fair Share. Centered around those ethics are twelve design principles that assist in building resilience into practically any human system. Bill Molison's definition, from the Permaculture Designer's Manual (one of the core books used in PDC's) states that "Permaculture is the conscious design and maintenance of agriculturally productive ecosytems which have the diversity, stability, and resilience of natural ecosystems. David Holmgren adds that Permaculture can play into many other systems, not just agriculture, and many good folks are putting Permaculture Design to work in the areas of finance, social justice, technology, and much more, including the musical masterpiece by Formidable Vegetable Sound System: Permaculture A Rhymer's Manual.