Congo meets Da Vinci Code. Primate and human intelligence are explored against a backdrop of old Catholic secrets. Throw in a larger than life team of heroes, stylish international travel, nail-biting firefights, nasty villains from China, and more narrow escapes than a Hardee Boys book, and you've got James Rollin's Bone Labyrinth. 
 Bone Labyrinth alternates between an A-story and a B-story, each focused on one of two brilliant sisters separated by an ocean, and each accompanied by half of "Sigma Force," an ultra-elite team of quasi-military-spy characters. 
 One sister, Maria, is the surrogate mother for Baako, a gorilla hybrid who is smarter than normal (and at least in the beginning, appears to be psychic as well). Her love for Baako and his love for her proves that she is as tender and caring as she is brilliant. Kowalski, a member of Sigma Force who knows sign language, is rough around the edges, but is able to communicate with Baako, thereby eventually earning love and respect from Baako and Maria. They are all kidnapped for the secrets of Maria and Baako's minds. 
 The other sister, Lena, has a knack for finding historical sites in Europe and South America that are easy to be trapped in by foreign assassins who are always right on her tail. Thanks to Sigma's Gray, who can see patterns when nobody else can, and his lover Seichan, who acts like Catwoman (badass babe), Lena is protected as she finds one clue after another about the origins of human life, but not without almost being drowned or shot at every turn. 
 The alternating plotlines and groups of characters may not be for all tastes. On one hand, the dichotomy keeps things moving along, creates cliffhangers, and prevents boredom with one topic or series of scenes. On the other hand, it's one tease after another. Usually the switches result in delayed gratification, stretching out the resolution to whatever conflict the characters find themselves in, but there are some instances where the constant switching is just a tease without gratification. 
 Bone Labyrinth is an ambitious novel, offering the possibility of explaining the moment in evolution known as the Great Leap Forward, or explaining Adam and Eve, or both. The book is like a treasure hunt, but the treasure is the understanding of human intelligence rather than material wealth. By that measure, Bone Labyrinth doesn't hit the bullseye, but at least it goes in the direction of the target. 
 It is a fun novel. The characters all have their own back stories and very specific traits, and from that standpoint they are well developed. They each have some weakness to balance out their enormous gifts and talents. But I think even James Rollins would admit that they're all over the top. I think it's intentional, because it is kind of fun to watch these combat geniuses at work. 
 If you love thrillers, or loved reading adventures as a kid (I really wasn't kidding about the Hardee Boys similarity), you will enjoy this book like I did. Rollins's ability to make science and history thrilling is impressive, but don't expect it to be quite like a Michael Crichton book--ultimately Bone Labyrinth's fun characters and rapid-fire action scenes are what animate this book, and science very important but somewhat secondary to that.