US photographer Michael Muller loves sharks and he's spent years travelling round the globe and diving into their world, without the safety of a cage, so he can get as close as possible to them. Now he's brought a collection of his photos together in a book - Sharks: Face-to-Face with the Ocean’s Endangered Predator - which not only showcases these beautiful creatures but aims to raise awareness about their plummeting numbers. He's been telling Nkem Ifejika how he fell in love with sharks.

(Photo: Great white, False Bay, June 2012. Credit: Michael Muller / Taschen / Image distribution CPi Syndication)