As the title gives away, this book is about the Martian Rangers. Not aliens. No, humans sorta like the Texas Rangers of old movies, but on Mars. A Mars that is every bit as wild and dangerous as the old west of stories.
This first book is the story of how the Martian Rangers got started. Things don't go well at first, but eventually, the Rangers pull through. It's a fun story, a mix of Science Fiction and Westerns.
I was primed to like this book - in many ways, it reminded me of my very first SF book, the one that set me on the path to SF fandom, was David Starr, Space Ranger by Isaac Asimov.