It would seem that we are not very efficient in the way that we use energy and materials to create wealth. We clearly need to do better, but what is the best approach for doing so? If we are seeking to develop truly sustainable societies, it would seem prudent to study the way that nature has developed highly sophisticated, interlocked and productive systems apparently without exceeding the carrying capacity of the planet or exhausting planetary resources. What are we doing wrong and what is nature doing right?