"Satan's Diary" by Leonid Andriyev is a philosophical book where the satirical hero, the most cynical and intelligent devil, talks about his impressions of observing people. The author successfully combines deep reflections on human nature, morality and faith with sharp humor and sarcasm. "Satan's Diary" is a dizzying analysis of society and individual psychology through the lens of the Prince of Darkness himself. This book captivates with its originality and depth of reasoning, leaving the reader open to new thoughts and reflections.