During my younger years, I devoured books like The Secret Seven. Not only are they adventurous, but the group is appealing, one which I would be glad to be part of. The Circus Adventure takes a slightly darker turn as the Seven encounter real criminals, hard-life types, after figuring out the clues ...
This is a great account of the basic events surrounding the Alamo and the fight for freedom from Mexico. It is long enough to give children more than a basic story, but short enough to read in one sitting.