Katherine Schwarzenegger Pratt's latest project drew inspiration from two childhood staples. In an exclusive interview with PEOPLE, the New York Times bestselling author and BDA Baby podcast host, 35, says her soon-to-be-released children's book, Kat and Brandy, was inspired by the horse she rode as a child, as well as the love for the animal that was passed down from her mother, Maria Shriver. "I've been an animal lover my whole life, and definitely a horse girl since I was little, and this book is based on my real-life pony named Brandy I had when I was growing up," Schwarzenegger Pratt tells PEOPLE. "The story here of bravery, courage and overcoming your fear is something that I experienced growing up, and I thought it was important to be able to put out a book with a positive message ... especially for young girls," she continues. "It is something my mom and my grandma always talked to my sister and I about, and they practiced what they preached," adds Schwarzenegger Pratt, referring to grandmother Eunice Kennedy Shriver and sibling Christina Schwarzenegger. "I grew up watching my mom ride, and I had that shared experience with her, so being able to have that come to life in this book was huge." Never miss a story — sign up for PEOPLE's free daily newsletter to stay up-to-date on the best of what PEOPLE has to offer​​, from celebrity news to compelling human interest stories. Kat and Brandy, which features illustrations by Petra Brown, follows a young girl named Kat, who overcomes her fear of horses after a prior riding incident when she meets a rescue named Brandy. Through patience and love, Kat and Brandy help each other face their anxieties and form an everlasting bond. Writing about her childhood horse, Schwarzenegger Pratt says, was always in the cards. Her first children's book, Maverick and Me, follows a story about dog adoption, while her second, Good Night, Sister, centers around a sisterly bond. (She is also the author of the self-love book Rock What You've Got, plus the inspirational The Gift of Forgiveness.) "This one, for me, is something that has been such a long time coming, and one that I've always wanted to do," Schwarzenegger Pratt explains. "I think with a book like this, there's obviously a mother-daughter relationship, but it was important for me to also be able to highlight the importance of having a shared activity for children — if that's with a friend or with a sibling or with a parent or an aunt or an uncle." The PEOPLE Puzzler crossword is here! How quickly can you solve it? Play now! "Being able to have that, and then especially being able to have that in nature, is such a huge gift," adds the mother of three. "I intentionally had those themes in there because they were such big themes in my childhood growing up, and ones that I wanted to have as part of the story of Kat and Brandy." Schwarzenegger Pratt, a self-proclaimed "huge animal lover," says telling these types of stories is so important, and something she has always been so passionate about. "I've been really lucky to have animals in my life since I was born," she says. "I really think that there's such healing power that comes with just being in the presence of animals, big and small, ... and to be able to have a connection with any animal, whether a goldfish, a hamster, a rabbit, a dog — whatever." In Kat and Brady, Schwarzenegger Pratt includes a long list of national resources that provide aid to horses and other animals alike, including the American Society for the Prevention of Cruelty to Animals (ASPCA) and the Best Friends Animal Society. Schwarzenegger Pratt works as an ambassador for both organizations. "Growing up, I have come across so many organizations that do incredible work with animals, whether it's animal therapy or animal rescue," she says. "It changes people's lives to be able to interact with animals, so it was important to me to be able to have resources included that support organizations that do great work with animals of all shapes and sizes, and to also be able to shine a light on the amazing work that so many equine organizations do." Now, as a mom, Schwarzenegger Pratt tells PEOPLE she loves reading to her children, as well as getting the chance to pass down her love of animals to them. She and husband Chris Pratt are parents to daughters Lyla Maria, 4, and Eloise Christina, 3, plus son Ford Fitzgerald, 8 months. (The actor, 46, is also a father to son Jack, 12, with ex-wife Anna Faris.) "It's a sweet thing now, because I take my kids around so many animals all the time," she says. "As someone who benefited from the presence of animals in my life and in my childhood growing up, to see that now with my own kids, it is really exciting." Schwarzenegger Pratt adds that "it's also wild now, to be able to reread so many of the books that made such a huge imprint on my childhood with my children. It is such a wild experience, and also such a huge blessing, of course." The PEOPLE App is now available in the Apple App Store! Download it now for the most binge-worthy celeb content, exclusive video clips, astrology updates and more! The Special Olympics ambassador also hopes that Kat and Brandy will inspire a whole new generation of young readers in the same way she found joy through stories that were read to her by mom Shriver, 69, and dad Arnold Schwarzenegger. "It's always a hope that when you put something out like a book, that it makes a memorable experience for a parent to read the book to their child or for a child to have the book read to them, or to read it themselves," she says. Kat and Brady, which will be released on Nov. 4, is available for preorder now, wherever books are sold.