Joel Sartore intends to photograph every animal in captivity in the world.

He is circling the globe, visiting zoos and wildlife rescue centers to create studio portraits of 12,000 species, with an emphasis on those facing extinction.

He has photographed more than 6,000 already and now, thanks to a multi-year partnership with National Geographic, he may reach his goal.

This book showcases his animal portraits: from tiny to mammoth, from the Florida grasshopper sparrow to the greater one-horned rhinoceros.

Paired with the eloquent prose of veteran wildlife writer Douglas Chadwick, this book presents a thought-provoking argument for saving all the species of our planet.