Here's a list of children's adventure and mystery book series or collections together with my comments on them. The book series appear in alphabetical order by author's name or pseudonym.
I started a search for children's adventure books after reading Hardy Boys books with my son, and wanting more diverse and better written adventure stories. After reading a few of the Hardy Boys stories, I concluded the Hardy Boys would need to retire on disability (much as would boxers) after the completion of the series due to the frequency at which they received concussive blows to their heads in the stories.
I have read four of these:
The protagonist has adventures all around the world. The stories were generally engaging and surprising, except for Hawaiian Sea Hunt Mystery, where a setting like the Hawaiian Islands could not compensate for a very predictable story line and minimally descriptive writing style.
This is a series of mysteries, one of the two main characters being a kid with a photographic memory. This series is probably more interesting for younger elementary school grade kids. The stories have mystery, suspense, and some hint of danger. They are relatively easy to read.
Clair Bee coached college basketball as well as wrote a number of books centered around a character named Chip Hilton playing baseball, basketball, and football in high school and college. These stories have lessons about sportsmanship, teamwork, and personal attitude. I've been reading the original, hardcover editions, since the more recent paperback editions have apparently been changed from the originals.
I started reading this series as a boy because of the science/electronics themes. The main character is a boy whose father runs a scientific research institution, and the protagonists are as scientific as they are adventurous. These were written by Hal Goodwin (the first three with another author) from the late 1940's to the 1960's. These are mostly no longer in print; a few of them have been reprinted and are currently available for sale new.
I enjoyed these immensely as a kid, and my son and I read through almost the entire series.
My comments and warnings about this series include:
If I had to pick the most personally inspiring of all the books listed here, it would be The Mad Scientists' Club. This series contains many stories of mostly ordinary boys experiencing extraordinary adventures. There is a predominant theme of using science and technology to pull pranks and do good deeds, all while thwarting a set of overly-self-important adults. The stories were written in the 1960's, so the science and technology is somewhat dated, but much of the adventuring is timeless. The part that amateur radio played in many of the stories inspired me to become an amateur radio operator as a teenager.
Two high-school aged boys have adventures solving mysteries and thwarting criminals. There's definitely some dangerous and threatening moments in these books, although the boys don't experience as many concussions as do the Hardy Boys.
I did not know about this series as a kid. These are well-written adventure books, and are some of my favorites on this page. My son and I enjoyed reading these together.
Troy Nesbit's books have boys encountering adventures outside in nature, typically in the southwestern United States. The books have physical adventures that challenge boys without the knock'em, sock'em stuff familiar to readers of the Hardy Boys series. At worst, the protagonists get followed sometimes, and in one story get locked in a shed that is built over a drinking water spring.
These books were written decades ago but they don't really lose much by being "out of date" because the adventures are low-tech and in nature. I'm glad I found out about these because of their engaging stories of adventures outdoors.
The protagonists of many children's adventure books seem to have a command of themselves and knowledge about the world that seems unrealistic; while I find it entertaining to read about the actions of these protagonists in the face of danger and challenges, I find it hard to identify with them because they seem to have so many advantages. They have had the focus, talent, and perseverence to have mastered many fields of knowledge as mid- to late- teenagers, and some have the incredible advantage of having generous and knowledgeable mentors.
The main protagonist in the Brains Benton series isn't so unreachable and the adventures of the two protagonists aren't so unapproachable. The Jimmy Carson character (through which the books are narrated in the first-person) is portrayed to be an average boy who exhibits heroism only after struggling with his fears of danger and natural reluctance to take risks. He has a friend and business partner (Brains Benton) who is what today we might call a geek or nerd. Brains appears to be self-taught in many fields of science and technology, and also has mastered other skills and fields of knowledge.
Brains and Jimmy are partners in a detective agency, and together they solve suspenseful mysteries, where the characters use every bit of their adolescent/teenage skills. While there is a sense of danger during some of the adventures, the actual encounter with violence is rare and relatively mild.