Societal and economic transitions have left numerous buildings redundant. Thanks to the esteem enjoyed by any sort of historic building fabric, an increasing awareness of sustainability issues as well as economic considerations, unused structures are now frequently being examined to determine what kind of new use might be suitable. These considerations take place in an area of tension between the poles of functional use of existing architecture as raw material, conscious inclusion of historical significance and radical new architectural interpretations. This volume presents more than 100 projects from around the world which are distinguished by a change of function they have undergone: from a police station to a cinema, from a bunker to an office, from a transformer station to a synagogue and from a swimming pool to an art center, among other creative re-uses. The innovative buildings and spaces are therefore emerging with layers superimposed on top of one another; the original function usually still provides the scale and structure, into which a new matrix of utilization is installed.