Earth is the blue planet. But our knowledge about the sea is rough and superficial. The author leads the reader on a voyage of discovery of the seas' inhabitants and adopts an unusual standpoint: theirs! We will thus find out how and where they move, if and in what way they court each other and reproduce, how they perceive their environs and interact with each other. The seas host a vast array of living species, many of which have yet to be identified. Getting to know the wealth as well as the fragility of the submerged world also means to protect it and to fight against abuse of its resources. All of us need to experience the sea and make it thrive.

Maria B. Rasotto is a naturalist and a marine biologist, and teaches Fundamentals of Biology and Behavioural Ecology at the University of Padua.