Viewed from outer space, it is hard to see how human life is organized. It is only when we get closer that we start to see the structure of individual communities. Closer still, and we see that these communities are highly organized, with a constant flow of people and materials adapting to an ever-changing environment. In a city, for example, we probably take most of the bustle of daily life for granted, but we can learn a lot from looking at the complex ways in which cities have grown, and continue to survive.

Although it may seem rather a large jump from a working city to a living cell - the organisation of different activities into different areas, the transport of raw materials, the building of new structures, the production of energy, the removal of waste, and effective communication systems - are all just as important for a cell as they are for a city.