I picked this up both as a children's librarian who wants to be knowledgeable about popular series for kids now and as a person who remembers 9/11 vividly and wondered how a book about a time-traveling dog would handle it. Color me IMPRESSED.
First of all, I like the setup. Ranger is a golden retriever who trained to be a search-and-rescue dog, but failed the test and is now a happy family pet. However, he has a mysterious first aid kit on a leather strap that periodically starts humming, prompting him to put his head through the strap and be summoned to another time and place where someone needs his help. Once he has helped them, he returns home. This brings him to a variety of dangerous situations in history, from the Underground Railroad to the Titanic to Hurricane Katrina, with his human family at home none the wiser.
Like the massively popular I Survived series, this series features fictional kids in real historical situations. This book feels extremely well-researched, and has notes, photos, and further reading suggestions at the end. At the same time, it's very kid-friendly. I would have DEVOURED this series as a kid!
And despite its cute kids-and-dog perspective, this book doesn't sugarcoat 9/11. For the first half or so of the story, Ranger is helping two kids get out of the North Tower. It's scary for them, but between the low visibility, their location, and the urgency of their escape, the author avoids having them actually see any dead bodies. However, when Ranger returns to the wreckage to help search for survivors, he does smell a lot of dead bodies under the rubble. There's also a moment when a woman stops the kids to ask what floor they were on, then runs off crying, and the kids realize that she must be looking for someone who was higher up. I teared up there, no lie. Kudos to the author for acknowledging that many people did not make it out of this disaster, and touching on that horror and tragedy, while still writing a book that shouldn't wreck young readers too badly.