The modern photolithographic technology on flexible and standard PCB supports has allowed the invention and development of novel and very robust Micro-Pattern Gas Detectors (MPGD: such as GEM, Micromegas, THGEM and others). This technology offers the potential to develop new detectors with very high spatial resolution, rate capability, large sensitive area, high operational stability, radiation hardness and good time resolution. In addition, the design of MPDGs is now mature for industrial production. Nowadays the progress is so advanced that the possibility to transfer these technologies to application fields beyond HEP such as medical imaging, homeland security, beam monitors and neutron detection has became fully realistic.

The 4th International Conference on Micro-Pattern Gas Detector, namely MPGD2015, is dedicated to review the current status of the different MPGD detector technologies, the new results, the novel concepts as well as the applications and future developments.

The Conference will be followed by a meeting of the RD51 Collaboration, the world-wide community dedicated to the development and the dissemination of the MPGD technologies.