Looks at how ancient microorganisms in primordial oceans transformed the chemistry of the planet over billions of years, eventually allowing the development of more complex forms of life, and how they continue to make life on earth possible.

The missing microbes -- Meet the microbes -- The world before time -- Life's little engines -- Supercharging the engines -- Protecting the core genes -- Cell mates -- Supersizing wonderland -- The fragile species -- The tinkerers -- Microbes on Mars and butterflies on Venus?