The first chapter of this book describes the problems of collective intelligence and its use in the context of digital archives. The other chapters then present different points of views on these issues by describing and analyzing concrete examples of use of collective intelligence to the benefit of digital archives. The digitalization of archives produces a huge mass of structured documents (Big Data). Due to the proactive approach of public institutions (libraries, archives, administrations ...), this data is more and more accessible. This book aims to present and analyze concrete examples of collective intelligence at the service of digital archives.