We have been isolating microorganisms from soil, water and other habitats and growing them as single cultures for over 100 years. Despite this, we know surprisingly little about microbial diversity. Less than 1% of all bacteria have been cultivated! This means that there are many new species to be discovered and understood. We use microbial products such as metabolites, enzymes and antibiotics in goods as diverse as washing powder, food and medicines. A major challenge in microbial ecology has been to attempt cultivation of the other 99% but first we must provide evidence that this 'unknown, uncultured' group exists and then understand their role in soil.