"Know and Know" - a series of books by the publishing house "Children's Literature" (Detgiz). At first it was called the Pioneer Library "Know and Know," then the name was shortened. The books of the series in an exciting game form acquaint middle and high school children with many concepts studied in the framework of the curriculum in chemistry, physics, mathematics, astronomy, biology, etc. The guys will learn how to make simple devices for experiments from improvised objects themselves, solve entertaining problems, prepare for quizzes and contests, arrange a holiday at home or at school, make gifts to friends with their own hands. Many schemes and drawings make the books of this series an indispensable help in school activities and leisure activities.