New technologies implie a new definition of money and its functions - medium of exchange, unit of account, store of value. We have to understand the changes of global economy, in order to face the challenges which are to come - unemployment, lasting development, etc. The first article of this dossier deals with the question of local money, and analyses its possible instauration - and its effects - in London. The second one presents a tool shaped to measure the impact of different actors on a local economy, while Tom Boyde article studies money flows and the problem of « money leaks ». The last article presents a project of monetary reform that would make the value of money creation a common resource, instead of a private one.