This book comprises 26 articles on the EChO science cases, mission pre-assessment and assessment, phase-studies, the payload, the instrumentation and software. They are reprints of articles published in a special issue on EChO - Exoplanet Characterisation Observatory of the journal Experimental Astronomy.Originally published in Experimental Astronomy, Volume 40, Nos. 2-3 (2015)

Giovanna Tinetti is Professor of Astrophysics at UCL. She works on galactic planetary science, trying to understand the chemical composition of planets in our Galaxy, how do they form and evolve and why are they so diverse. She was lead scientist or principle investigator of several international projects. She is an Editor of Icarus, the American Astronomical Society DPS journal and guest editor of the special issue on EChO, Experimental Astronomy, Springer (2015).Pierre Drossart is Director of LESIA (Laboratoire d'Etudes Spatiales et d'Instrumentation en Astrophysique), at the Observatoire de Paris. His field of research is planetology and the physics and spectroscopy of planetary atmospheres and their dynamics. He is envolved in the development of instrumentation like infrared spectrometers, spectro-imagers and space intrumentation. He has been co- and principle investigator of several space experiments.