I read a few of Ron Roy's "A to Z" mysteries and was so impressed that I grabbed the first two from the Calendar series for younger readers. I'm happy to report that those volumes were just as entertaining.
Roy has three sets of mysteries. The "A to Z" mysteries, (26 volumes for the 26 letters and then three bonus volumes), are for older chapter book readers. The "Calendar" mysteries, (surprise - 12 volumes), are for younger readers and, in a clever twist, feature the younger siblings of the protagonists from the "A to Z" set. The third series features mysteries that take place at various national landmarks in Washington, D.C.
Both the "A to Z" books and the "Calendar" books feature an appealing set of characters, fair mystery plots, a bit of action and decent secondary characters. The Calendar books are like junior junior junior versions of the Hardy Boys and Nancy Drew mysteries. They have younger heroes, they are shorter, there are fewer twists and turns, there's very little danger, and the mysteries are a lot tamer.
But that said, they have many of the same strengths. The four heroes, (first graders Bradley, Brian, Nate and Lucy), play equal roles, with no apparent bias between boys and girls. There is the same authentic and mutually supportive friendship among them. Adults are generally patient, resourceful and dependable, (when they aren't the villain in disguise). There is a good balance between clue hunting and figuring things out. Probably the biggest difference between these books and the sets for older kids is that there is very little adventure, in that the kids are rarely chased or trapped or threatened or menaced. These are much milder on that score.
The mysteries are conventional, but I mean that in a good way - clues are fair, red herrings are fair, and the resolutions are logical. There are some convenient coincidences, but that's par for the course, especially in a relatively short chapter book. But even then the emphasis is on logical thinking and deductive reasoning, which is something that is often wanting in more fanciful and less thoughtfully plotted books for this age group.
In the "January" volume the kids get an alien invasion scare. Is it real or a prank? The kids are very clever in gathering clues and thinking things through, although there is a bit of a thrill behind the idea that the invasion might be real. This one is less about detecting and solving and more about pranking.
In the "February" book we have a full blown mystery. Who abandoned a pet rabbit in the classroom, for adoption by the class? The kids follow clues and do actual detective legwork, and while everything falls conveniently into place, the solid bones of a decent mystery for new readers are clearly in place.
So, these are kids' books, but they aren't silly, and there is no hint of fart/booger humor, which may have its place, but not necessarily here. The writer treats the young chapter book reader with a lot of respect and I would expect that these stories would be a satisfying read for a youngster. I doubt you can ask for much more than that at this level and I could see a kid just eating up these tales and this likable cast of characters.
Please note that I found this book while browsing the local library's Kindle books, and downloaded it for free. I have no connection at all to either the author or the publisher of this book.