This book takes a close look at the species undertaking the longest, most challenging or most bizarre journeys of all. They range from whales to wildebeest, terns to turtles, and bats to butterflies. Some fly, some swim,others run, walk or scuttle, but allhave earned their right to be known a the greatest travellers one earth. We examine the animal itself - its biology and ecology, how it leads it life and why it migrates. Then we journey with it on its migration, exploring what we've learned of how, where and when it travels, and what mysteries remain to be uncovered.