Fifty years ago there were close to half-a-million lions in Africa. Today there are around 20,000. To make matters worse, lions, unlike elephants, which are far more numerous, have virtually no protection under government mandate or through international accords. This is the jumping-off point for a disturbing, well-researched and beautifully made cri de coeur from husband and wife team Dereck and Beverly Joubert, award-winning filmmakers from Botswana who have been Explorers-in-Residence at National Geographic for more than four years. Pointing to poaching as a primary threat while noting the lion's pride of place on the list for eco-tourists-an industry that brings in 200 billion dollars per year worldwide-the Jouberts build a solid case for both the moral duty we have to protect lions (as well as other threatened "big cats," tigers among them) and the economic sense such protection would make...