Our bodies are filled with bacteria that have rich social lives and, just like people, these microbial neighbours and families do not always get along. In some cases, it is the bacterial equivalent of The Sopranos. Dr Sally Le Page delves into the bacterial dramas of loners, crowd-lovers, backstabbers and do-gooders that are fighting it out in the world and inside our bodies. Co-operation, cheating and selfish behaviour can all lead to benefits or disease so scientists are studying this behaviour to help produce new medicines and clean up our environment.