Exploring Space (1958)
While The Complete Book of Space Travel was aimed at teen and pre-teen boys, the 1958 book Exploring Space was looking for a younger audience (still of boys, mind you, since we all know that lady-parts get confused with all that science and math).
Below are sample pages from the book, including one that some little tyke got after with a brown crayon.
While some scientists are trying to find out how to land rockets safely, others are learning what kinds of suits space travelers will need. They pump air out of a room, so it is like space. Men who are inside wear space suits to test them. The men breathe through a hose connected to an oxygen tank.
Next a man may test a space suit in a three-stage rocket. Perhaps he will pilot stage three after it breaks away and speeds into space. He will go too fast to feel the pull of gravity. His body will lose all its weight. He will float around the cabin, if he isn't strapped in place. Will the first space traveler like the ride? When he lands, he will tell us.
Other men will follow the first space traveler into space. They will test bigger and bigger rockets. And so scientists will learn how to build great big rocket ships. These ships will fly around the world in an hour.
In time, scientists will know how to build rocket ships that can carry people to the moon. After the moon, what next? Perhaps people will visit other worlds in the sky.
Perhaps when you are grown-up, rockets will be as common as airplanes are now. Then you and all your friends will be space travelers. Rockets away!