Currently, severe dieback of Fraxinus spp. is observed in most European countries. This is an emerging disease, which results in massive tree mortality, threatening the existence of Fraxinus over the continent. It is caused by Hymenoscyphus pseudoalbidus, alien and invasive fungus, origin of which remains unknown. Currently, many European countries have national research programs on Fraxinus dieback, focusing on numerous aspects of the biology and ecology of the disease, but the activities are scattered. Aim of the FRAXBACK is, through sharing and synthesis of available knowledge, generate comprehensive understanding of Fraxinus dieback phenomenon, and to elaborate state of the art practical guidelines for sustainable management of Fraxinus in Europe. The Action will be implemented through innovative interdisciplinary approach, and will include forest pathologists, tree breeders and silviculturists. Its deliverables: i) guidelines for sustainable management of Fraxinus in Europe; ii) European database for dieback-resistant Fraxinus genotypes/families/populations and established/planned progeny trials; iii) illustrated digests/leaflets/brochures on Fraxinus dieback; iv) disease distribution maps; v) website; vi) book. FRAXBACK is comprised of four Working Groups: WG1 Pathogen; WG2 Host; WG3 Silviculture; WG4 Dissemination and knowledge gaps. Its duration is 4 years, including two MC/WG meetings and four STSMs per year, and one international conference.