CRACKER IS ONE OF THE UNITED STATES ARMY'S MOST VALUABLE WEAPONS: a German shepherd trained to sniff out bombs, traps, and the enemy. The fate of entire platoons rests on her keen sense of smell. She's a Big Deal, and she likes it that way. Sometimes Cracker remembers when she was younger, and her previous owner would feed her hot dogs and let her sleep in his bed. That was nice, too. Rick Hanski is headed to Vietnam. There, he's going to whip the...