Book excerpt: Omar Rivera, an office worker who is blind, and his guide dog, Salty, were on the 71st story of the World Trade Center’s North Tower on the morning of September 11, 2001 when terrorists hijacked two planes and crashed them into the World Trade Center towers. Omar’s coworkers raced to the stairway to escape the burning building. With chaos all around, Omar told his dog to guide him down the stairs. Would Salty be able to lead his owner to safety? In this book, young readers will meet the brave dogs that helped people during and after the deadly terrorist attack. From guide dogs that calmly led their owners to safety, to the 300 search-and-rescue dogs that used their powerful sense of smell to try to find survivors in the rubble, these incredible animals were part of the largest canine rescue operation in U.S. history. With true stories and full-color photographs of dogs working at Ground Zero, this book is sure to appeal to dog lovers everywhere.