What to read after Rescuing Riley, Saving Myself?

While hiking on a solo vacation in a remote, uninhabitable region of Arizona, Zachary Anderegg happened upon Riley, an emaciated puppy clinging to life, at the bottom of a 350-foot canyon. In a daring act of humanity that trumped the deliberate savagery behind Riley’s presence in such a place, Zak single-handedly orchestrated a delicate rescue. What didn’t come out in the initial burst of publicity this story received is that Zak and Riley’s destinies were intertwined long before they improbably found each other. For much of Zak’s childhood, he was at the bottom of a veritable canyon himself—a canyon whose imprisoning depth and darkness was created by bullies who just wouldn’t quit and parents who weren’t capable of love. From the age of five, Zak was everyone’s favorite target. 
When Zak came upon Riley, the puppy’s condition bespoke his abusers’ handiwork—three shotgun pellets embedded beneath his skin, teeth turned permanently black from malnutrition. The meeting was one of a man and a dog singularly suited to save each other. As a former US Marine sergeant, Zak was one of only a few people with the mettle and physical wherewithal to get Riley out. And in rescuing him, Zak was also attempting to save himself, conquering the currents of cruelty that swelled beneath his early life and always threatened to drown him.