I feel as though I read the same book 28 times. If you’re looking for a chapter book series for kids, this wouldn’t be my top recommendation. There’s no character growth, the same exact lines are repeated for Jack in every single book “oh man,” “oh brother,” and a surprising number of ghosts & mentions of death. These kids are sent into the most dangerous events in history by an adult which my child and I both found confusing and distressing. My four year old did enjoy them since they were incredibly easy to follow, which garnered the third star.