The 31st European Conference on Surface Science (ECOSS-31) will be held at the International Convention Center of Barcelona (www.ccib.es) from August 31th to September 4th, 2015. ECOSS is a well established meeting with a longstanding tradition that started back in 1978 in Amsterdam and is organized jointly by the Surface Science Division of IUVSTA and the Surface and Interface Section of the European Physical Society. It provides a comprehensive overview of the state-of-the-art surface physics and chemistry, discusses recent advances and current problems, and points out the prospective development of the field. Experimental as well as theoretical aspects are addressed, covering mainly basic but including also applied research.