The depths of the oceans are the last example of terra incognita on earth. Adamowsky presents a study of the sea, arguing that - contrary to popular belief - post-Enlightenment discourse on the sea was still subject to mystery and wonder, and not wholly rationalized by science. She portrays the sea as a theatre of mystery, accessible only with considerable technological effort. It is this unknowable quality which locates the sea at the intersection between science and our imagination.