Atheism: notion and kinds

The general concept of atheism is defined, and also the most widespread kinds of atheistic world-outlook are described. The author believes, that, as a rule, the atheism is a shadow system of any traditional religion. The atheism is not to the full independent, it has no his own nature. Therefore it is more correctly to speak not about atheism "in general", but about "Christian atheism", "Muslim atheism", etc. Several specified conditions of existence of "religious atheism" and "non-religious atheism" are mentioned.