Because rivers and lakes are commonly turbid and murky, many creatures that live there are invisible to traditional wildlife film-makers. So although many people are familiar with the inhabitants of tropical reefs, and even the deep oceanic trenches, it is the water right under our noses that we know least about. And yet these creatures at the top of the freshwater food chain are every bit as spectacular - and dangerous - as those that prowl the oceans.
Man-eating catfish in the Himalayas, wandering bullsharks in the rivers of Australia, man-sized super-piranhas that snack on the dangling genitals of swimmers in the Congo: these are only a few of the freshwater leviathans Jeremy Wade encounters in River Monsters: True Stories of the Ones That Didn't Get Away, the long-awaited book adaptation of Animal Planet's all-time highest-rated show.