Fiber sensors allow continuous monitoring of physical, chemical and biological parameters that are interesting for a wide range of applications in civil and industrial engineering. Among other good properties, fiber sensors are small and lightweight, they can be used in harsh environments with remote monitoring, and they are immune to electromagnetic interference. The use of fiber sensors is thus becoming widespread, but new applications and requirements are emerging that require a substantial research effort. New sensing devices and techniques are required for specific environments (e.g. radiation-tolerant sensors), new interrogation techniques have to be developed and tested, and procedures to achieve the standardization of the existing sensors should be put forward. The aim of this working group in the Action is transversal, i.e. to use the knowledge created by the other working groups towards the development of new, useful devices in fiber sensing. Measures have been taken by the MC to ensure that there is a transparent exchange of knowledge between the four Working Groups in the Action. Members within the MC will perform the liaison between the Working Groups, so as to guarantee a bidirectional flow of information.