PREFACE: The Milky Way Unravelled by Gaia: GREAT Science from the Gaia Data ReleasesN.A. Walton, F. Figueras, L. Balaguer-Núñez and C. SoubiranEAS Publications Series, 67-68 (2014) 1-3DOI: https://doi.org/10.1051/eas/1567001
