A while back I read the first book in the Olivia Wolf series, Olivia Wolf and the Moldy Sandwich. I don’t remember the story itself, but I remember liking it. It was a fun, cute story about monsters and humans living harmoniously together. There was a mystery and they solved it. I then read book two, Olivia Wolf and the Night of the Giant Monsters, and the same thing was on those pages: a cute, fun story with a mystery to solve. Then recently I saw the title Olivia Wolf and the Trip Through Time and thought, “Oh. I haven’t read this… is it two …no it’s book four! Well guess I better get book three (Olivia Wolf and a Million Olivias) first.” And I found an online copy and read. I then realized I had already read it, but hey! No harm no foul. 
Book three is Olivia Wolf and a Million Olivias by José Fragoso. This book is about a party at a Chuck E Cheese/Five Nights of Freddy like pizza joint where the kids go to have birthday parties. One such party has the kids wondering why Olivia is being so mean after she comes out of the ball pit. Well, that’s because it is not the Real Olivia, but a copy. Many many copies in fact. So, our gang of friends hunt down the clues to how they can solve the mystery of Too Many Olivias and find the biggest clue is from the past of Olivia’s own family. 
I then said, well, might as well read book four (due late April/early May 2025) as long as I have access to the online reader copy. Olivia Wolf and the Trip Through Time is still cute and fun, but there really isn’t a traditional mystery. This time we take our Mummy friend back in time to ancient Egypt to find a cure for his illness. In the process we learn that the time machine has some odd (and convenient) side effects, being with your friends is a great magic and being brave comes in all shapes and sizes. There is a little history, too.
Overall, the books work for an aged 6 to 9 reading age, but can be read to a younger audience as well. The illustrations are funny, quirky, simple, and tell the story plus are good support for the story itself.