The "Associazione di Consulenza in Diritto del Mare" (ASCOMARE) is pleased to inaugurate its Yearbook on the Law of the Sea (YLoS). The First Volume focusing on "Law of the Sea, Interpretations, and Definitions" aims at examining the content and legal scope of undefined terms of the UN Convention on the Law of the Sea (UNCLOS) and other related instruments, against the backdrop of State practice, international jurisprudence, and preparatory works. The volume strives to promote a uniform interpretation and application of the provisions of UNCLOS, as well as to provide an influential legal viewpoint on the meaning of undefined terms and phrasal lexemes of the law of the sea. ASCOMARE is an international platform established in 2018 to provide pro bono legal consultancy and technical assistance to Governments, public and private entities as well as NGOs. The main goal of ASCOMARE is to facilitate the widespread and uniform implementation of the law of the sea, in line with Sustainable Development Goal 14.C ("Implement and enforce international law of the sea") of the 2030 Agenda.