The book by the famous German animal behaviorist Norbert Sachser presents the current state of the science of behavior. The author’s main conclusion is that over the past 20 years there has been a paradigm shift in ethology: “little brothers” have become closer to humans. They are sad and happy, just like us. They are cunning and deceive, they learn new things all their lives, they have their own character and are aware of their “I”. Where is the border between them and us? How are we different from animals and what can we learn from them? How do mice escape Alzheimer's syndrome and how do guinea pigs avoid stress? How many words can dogs remember and can birds recognize themselves in the mirror? What are scientists studying animal behavior doing today? What methods do they use and what other sciences come to their aid? The reader will find answers to all these questions in this book. The publication is addressed to everyone who is interested in animal behavior.