This is the series that launched a thousand reading habits. Mary Pope Osborne figured out the exact formula to get first and second graders hooked on chapter books: short, episodic adventures with just enough educational content to make parents feel good about the screen-time alternative.
The magic here isn't actually the time-travel premise—it's that kids genuinely want to read the next one. Jack and Annie are likable without being saccharine, the historical settings provide novelty, and the reading level hits that sweet spot where kids feel accomplished without struggling.
The downside? It's formulaic as hell. Once you've read five, you've basically read them all. Older kids or strong readers will find them predictable and simplistic. But for that narrow window when your kid is 6-8 and learning to love reading? These books are absolute gold.
The religious controversy over 'magic' is overblown—this is Narnia-level fantasy, not occult literature. If your family is comfortable with fairy tales, you're fine here.
Bottom line: Not literary masterpieces, but exceptional training wheels for independent reading. Stock up at the library and let your early reader devour them.