This multi-authored book brings together new work, from a wide range of disciplinary vantages, on pre-Christian religion in the Celtic-speaking provinces of the Roman Empire. The chapters are the work of international experts in the fields of classics, ancient history, archaeology, and Celtic studies. It is fully illustrated with b&w and colour maps, site plans, photographs and drawings of ancient inscriptions and images of Romano-Celtic gods. The collection is based on the thirteenth workshop of the F.E.R.C.AN. project (fontes epigraphici religionum Celticarum antiquarum), which was held in 2014 in Lampeter, Wales.