This throws me back to a reading list from the seventh grade. There it sat since the early 1950s. Now I find it at a library used book sale. I rescue it from the discard pile. Why not give it a shot? It turns out that the principal characters might have been cousins to the Hardy Boys who uncover a plot and set out to rescue the Earth colony on Mars from annihilation. This is a good book for teenagers and a suitable introduction to science fiction: not overpowering in scientific detail, with interesting but sketchy exposure to technological advancement, and certainly conjuring up some odd alien lifestyles.