Principles of Permaculture
The term 'permaculture' was coined in 1978 by Australians Bill Mollison & David Holmgren as shorthand for permanent human culture.  Historically, it's focus has been on small scale intensive agriculture, growing many different species of plants together in patterns which emphasize mutually beneficial interactions between various plants and animals.    Each element (plant, animal, rock, wall, etc.) is selected to perform multiple functions (fixing nitrogen, attracting pollinators, discouraging pests and disease, providing shade, food and medicines for humans and other animals, etc.).  In turn, each function is performed by multiple elements, creating a network that is resilient to disturbances (an early frost, for example). 
Done well, permaculture reduces the need for human labor in producing food, medicine and other needs.  It does so by leveraging nature's services for our benefit, working with nature rather than against it.  Nitrogen fixing plants and composting in place is used to maintain proper chemical balance in soil rather than constantly chasing the right mixture using chemical  fertilizers, for example.  This approach focuses on design and deep understanding of nature.
It is important to note that permaculture is NOT just about landscape but may encompass buildings and other elements of the built environment.  Passive solar heating, natural ventilation, renewable energy production, rain water harvesting and waste recycling are all important considerations.  Selection of building materials to reduce cost and enhance occupant health are also part of this design method.
Permaculture, then, encompasses many elements of integrated regenerative design discussed elsewhere on this site.  It is a great tool, though not the only one we employ in our practice.   For an example of one of our permaculture inspired designs, please click here.