ABSTRACT
My essay reflects the achievements of the Challenger Expedition, starting with the basic exploration of the world ocean, then moving on to key scientific issues that remain unresolved at the end of the twentieth century and to the new tools that will help us address them in the next twenty years. After discussing the practical exploitation of the new under standing and methods, I shall close by asking who will pick up the baton and lead our subject in the twenty-first century as Britain did in the nineteenth.
