If the Open Data (Open Data Released or they say in France) is not a theme quite recent, it has so far not yet reached a level of sharing ideas about the place of his or notoriety to take its rightful role in the debate. In writing this title, Simon Chignard commits an excellent and commendable clarification exercise, illustration and placed in context - locally and internationally the rest. The overview will satisfy the honest man and the expert. Expert, it is nonetheless pedagogue and variety of illustrations and contextual examples give all reading levels of satisfactions and valid reasons to continue. The Publisher's plan is a good progress in the debate and the details and never the foreign initiatives - we are not an island - do not miss to take us to modesty in case of "great and unique idea." I look forward to another author - an INRIA researcher or other university - delivers a more technical topics that complement where S Chignard cleared and has amply illustrated, may receive a formal technical background "hardcore" on formats data, the joys of Big Data and the universe of Databases flat ... A "must read".