By now, we may begin to appreciate the difficulty in knowing the precise history and evolution of the Grand Canyon. It may appear to be an impossible task to look back through so much time and so much erosion and definitely piece together a coherent story of how this great gorge was carved.

    Thus begins Wayne Ranney into summing up what he's presented us with in Carving Grand Canyon: Evidence, Theories, and Mystery ($14.95), a book in which Ranney presents us with what is known about the Grand Canyon, and with what is unknown.
    Any guess as to whether what we know about the iconic canyon outweighs what we don't know about it? One of the few certainties is that erosion carved the canyon. Beyond that, well, let's just say the canyon continues to provide ample opportunities for research into its origins.
    ... the many geologists who have devoted their careers to studying the canyon cannot resolve its age more precisely than somewhere between 80 and 6 million years, and they still debate whether it was formed rather catastrophically or over a much longer period of time, writes Ranney, himself a trained geologist who has spent a good deal of his life pondering the canyon's origins.

    Ranney's book, published by the Grand Canyon Association in 2005, won honorable mention in the Nature and Environment Category at the 2006 National Outdoor Book Awards.
    Clearly written and beautifully illustrated with color photographs of the canyon and maps and diagrams explaining the geologic forces at work, the book is not a heavy, geologic treatise. Rather, it entices one into turning the pages via a conversational tone, much as if you were standing on the South Rim discussing the canyon face-to-face with Ranney.
    Along the way to the end of this 160-page book, the author outlines the various scenarios that might have created the canyon, touches briefly on some of the earliest explorers who pondered its origins and their theories, and, of course, explains the geologic formations exposed in the canyon.
    Yet perhaps what makes this book so intriguing, beyond the journey Ranney takes us on, are the many questions that still linger today, more than 450 years after several men from Francisco Vásquez de Coronado's party exploring the Southwest stood on the canyon's rim, frustrated that they couldn't find a way across.
    Grand Canyon is a puzzle, a mystery, an enigma, Ranney tells us. It appears to have been carved through an uplifted plateau, ignores fault lines, may have been born by a river that once flowed the other way, is possibly quite old or quite young -- or both -- and is set within a more mature landscape.
    Mysteries are intriguing things, they keep us asking questions and coming back for more. While Ranney does a good job relaying what is known about the Grand Canyon, he does a wonderful job of encouraging us to return again and again to the canyon, to look off one of its rims into the deep abyss, and ponder what played out to create this incredibly beautiful void.