I know many of you had this book and may have forgotten it. For me I had many in the "How and Why" series because they were on sale in supermarkets, especially as paperback copies. So I could often convince Mom that I could put a book in the basket. Many of them were published around the early 1960s but got reprinted and slightly updated later on. This is a 1967 reprint of the1962 book.
I remember reading my paperback copy until the pages started falling out.
Text focuses on the solar system, history of rockets, human factors in space travel, and current exploration efforts. Illustrations of rockets, astronauts, a manned landing on the Moon. Updated text through the editions but the illustrations remain the same. "How and Why Wonder Books" #5068. Also found in softcover ("How and Why Wonder Books" #5048). Also 1967, 1969 editions.
I liked their use of a delta-wing vehicle to illustrate how they orient their ships.
They show the possibilities and progression we were to take to explore other planets.
They also had some nice illustrations implying how we could dream of what was to come.
Finally the illustration of the stages to the Moon: space station, a lunar lander, and man on the moon bring back simpler dreams of how our space future was soon to come.