The study of the highest-redshift galaxies and quasars is critical to our comprehension of how early galaxies helped shape the Universe as we see it today. In particular the properties of the interstellar medium (ISM) of these galaxies provide important clues towards understanding the complex interplay between the accretion of baryons onto galaxies, the physics that drives the buildup of stars out of this gas, the subsequent chemical evolution and feedback processes, and the reionization of the Universe. The Atacama Large Millimeter/submillimeter Array (ALMA) continues to play a fundamental, groundbreaking role in the characterisation of the ISM of high-redshift galaxies. Observations of the dust continuum emission, atomic fine-structure and molecular lines arising from high-redshift galaxies are now carried out routinely, providing ever more constraints on the theoretical models of galaxy formation and evolution in the early Universe. The aim of this symposium is to bring together the observational and theoretical high-redshift ALMA communities in order to discuss the most recent results in the rapidly evolving field of galaxies at redshift z~4 and above. This symposium also aims to explore future synergies between ALMA and the Extremely Large Telescope (ELT), one of the future flagships of European Astronomy, for high-redshift science.