-- USA TODAY BESTSELLER -- THERE ARE PLENTY OF WAYS TO DIE in the Grand Canyon. Forensic geologists Cassie Oldfield and Walter Shaws investigate one way: trouble on the canyon's Colorado River. Stranded raft. Life vests unused. Rafters missing. The only clue to the fate of the rafters is a bag of pebbles caught in the bowline. Following that clue, the geologists uncover a hellish scheme. Not only are the rafters...