nd This book collects the scientific contributions from the lecturers at the 2 edition of the "International School on Marine Chemistry" held in Ustica (Palermo, Italy) from 5 to 12 September 1998. The School was planned with the aim of giving an overview about the chemical processes occurring in the marine environment and the more recent ana- lytical methodologies for their study. The School was organised under the auspices of the Italian Chemical Society and with the financial support of the Marine Reserve of Ustica Island, the Committee for Environment of Italian CNR, the University of Palermo, the Provincia Regionale of Palermo and the Shimadzu-Italia Corporation. The book has been printed with the fi- nancial support of the ''Assessorato Ambiente" of the Provincia Regionale of Palermo. All the participants, about a hundred including the lecturers and the Organising Committee, are grateful for the generous support of the agencies. A particular ac- knowledgement from the Editors is to all the lecturers for their availability and cour- tesy and for the high quality of their scientific contributions.