The Office for Science in Garching (Germany) at the European Southern Observatory (ESO) organised the second edition of the Hypatia Colloquium Series. Announced for the first time in November 2020, the Hypatia colloquia foresees a series of 20 min talks given by early career astronomers (up to 3 years from the PhD). In a few words, the Hypatia Colloquium Series is meant as a channel to allow excellent young researchers to show the results of their scientific work to a broad audience. This book collects the scientific contributions of most of the speakers of the first series in the form of proceedings.