<p><i>Humans have identified just a fraction of the 2.2 million species living in the sea. Roughly 91% of all marine species remain unknown: myths still to be written, discoveries still to be made, blank pages with room to dream . . .</i><br><br>As a small boy, Bill Fran¿s was frightened of deep water. Until a chance encounter with the elusive sardine set him on course for a life in marine science: a mission to better understand, and preserve, the underwater world, to find his place in that ecosystem and learn how to converse harmoniously with the ocean.<br><br>In a series of exquisitely rendered vignettes of marine life, Fran¿s invites us on a whistle-stop global tour to reveal the mysteries of the sea, beginning with the simple eloquence of the sardine. He unpicks the sound of the sea - an underwater symphony orchestra voiced by a choir of fish - and deciphers the latest scientific discoveries on the immunity of coral and the changing gender of wrasses. We visit the depths of underwa