IAU Symposium 388 brought together solar and stellar researchers on coronal mass ejections (CMEs), which are of great importance because of the intriguing physics involved in their origin and how they impact planets around the Sun and other stars. These proceedings are a collection of peer-reviewed papers presented at the symposium. The scientific program included solar sources; the interrelationship among observed phenomena such as CMEs, flares, and eruptive prominences; the detection and modeling of stellar CMEs; particle acceleration by CMEs; CME propagation into the interstellar medium; and their effects on planets around their host stars. The symposium demonstrated that a synergistic approach to solar and stellar CMEs is essential in understanding how magnetic energy is stored and released from spatially confined magnetic regions on the stars and their consequences for star-planet relations over various timescales.
