Dog owners know how how much joy our beloved canine companions bring to our lives.

They enrich us in small and undramatic ways every day—by making us laugh, keeping us company, and offering us unconditional love. My new National Geographic book, Devoted, focuses on 38 stories about the bond between extraordinary dogs and their humans—five of which are described below. (Related: Can Dogs Feel Our Emotions? Yawn Study Suggests Yes.")

We also want to hear the story of you and your dog. Please share your photos with the National Geographic Your Shot community through October 2.

Jasmine

In 2003, an English policeman discovered a greyhound cowering in a locked shed. The dog was severely malnourished, filthy, and clearly abused.

The policeman took her to the Nuneaton and Warwickshire Wildlife Sanctuary, a place founded and run by Geoff Grewcock to care for sick and injured animals. And so an act of fate would change the life of not only a dog and a person, but hundreds of other animals as well.

"When I first met Jasmine, you could tell she had been emotionally devastated but was a gentle dog by nature," Grewcock said. "And soon, she started nurturing the other animals."

Jasmine became famous for playing mother over the years to puppies, foxes, a fawn, 4 badger cubs, 15 chicks, 8 guinea pigs, 15 rabbits, a deer—and one of her favorites, a goose.

"There are certain things only an animal mother can provide, and Jasmine provided it," said Grewcock.

Jasmine passed away in the fall of 2011, an event marked by worldwide donations made in her honor to the sanctuary, which continues to care—if not with Jasmine's personal style—for animals in need.

"Her passing was so sad," said Grewcock. "But she was a legendary animal, and her legacy continues. "

Wilma

Thanks to Wilma, Steve Sietos may very well be the world's only fireman/herbalist/energy healer. It was love at first sight when Wilma the pit bull was brought into Sietos's Brooklyn firehouse. She was hungry and sick, her hair was matted, her tongue hung out at a weird angle—but she never stopped wagging her tail. (Take National Geographic's dog quiz.)

But after Wilma was diagnosed with cerebral palsy, Sietos went bankrupt spending $8,000 on futile treatments.

"I said to myself, 'No more vets,'" he said. "I started researching herbs and flower essences that help immune systems, and that was the beginning of her healing."

It was also the beginning of Sietos's additional career as a clinical herbalist. He now helps both animals and people.

As for Wilma, she's improved and has taken on a role usually reserved for dalmatians: Firehouse Fido.

Wilma was rescued by the captain of Steve Sietos’s firehouse; Sietos later adopted her.

Pearl

A little enthusiasm can take you far—in the case of Pearl the black lab, all the way from a California pound to Haiti.

At the animal shelter, a group that trains seeing-eye dogs saw promise in her. Then they got to know her.

"Halfway through testing her, the rescue said, 'This dog is way too hyper,'" said Pearl's owner and handler, Los Angeles firefighter Captain Ron Horetski.

That was music to the ears of the National Disaster Search Dog Foundation, since search and rescue missions require round-the-clock work and a "Wait, I'm just getting going!" attitude. (Watch a video of working dogs.)

After arduous training, the pair was deployed in 2010 to earthquake-stricken Haiti as part of the first ever international canine search and rescue team. The pair also traveled to Japan after the 2011 tsunami.

When at home, Pearl accompanies her owner 24/7, as part of the program's guidelines, but "she's a work dog, so she's not on my lap watching TV at night," said Horetski.

"And we don't go to the dog run to play, because she needs to be ready and have the energy for an emergency. But she's so much more than a pet to me. She's my partner."

Pearl, a Labrador retriever who lived in a shelter, is a search-and-rescue dog who helps after natural and man-made disasters.

Luca

Sometimes, in order to really listen, it helps when you can't hear anything at all.

That's the case with Luca, a deaf pit bull whose gift as a therapy dog comes from what others might perceive as a disability.

Luca, who was adopted as a puppy from a shelter, was trained by his owners, Brooke Slater and Dave Goldstein, to make constant eye contact so he could follow their signed commands.

For the at-risk or disabled youths with whom Luca now interacts, that can often mean feeling—and being—recognized for the first time. "He doesn't give these kids a choice but to make eye contact, because he walks right up to them and demands it," said Slater.

Luca—who inspired Slater and Goldstein to start Bruised Not Broken, a Facebook page devoted to pit bull rescue that has more than 100,000 followers—is also an ambassador.

"We are part of a program that teaches empathy and compassion. When Luca walks in the room and they see a pit bull, kids hit the deck screaming," Slater said with a laugh.

"So the first lesson is, 'No prejudice. Decide how you feel after spending time with him.' This is the work he was born to do."

Luca is a deaf pit bull whose gift as a therapy dog stems from what others might perceive as a disability. Even though Luca is deaf she has learned to follow her owners’ instructions by their special hand signals.

Chancer

The joy a dog can find in comforting the stricken has transformed the Winokur family, whose adopted son, Iyal, displays symptoms of fetal alcohol syndrome.

The teenager, who has damage to his brain and central nervous system, experiences rages, delayed emotional growth, and sleepless nights—all of which were undoing a family exhausted by a decade of round-the-clock care.

But within 24 hours of being paired with Chancer, a golden retriever, the family's lives were transformed. On his first night in their home, he crawled into Iyal's twin bed to sleep beside him; after years of nocturnal disruptions, the entire family finally slept until the sun came up.

Now, when Iyal has a temper tantrum, Chancer nestles next to him or lies on top of him to soothe him, and "the rages don't escalate the way they used to and they don't last as long," said Iyal's mother, Donnie Winokur.

Chancer also makes it easier for the family to enjoy their relationships with the teenager.

"I have a child with a severe disability but a huge kind heart and soul—and it's about making sure we have access to that heart and soul," says Winokur.

"Chancer helps us do that."