"21 Lessons for the 21st Century" is a book by Yuval Noah Harari that explores the challenges and questions facing humanity in the modern world. It addresses topics such as technology, politics, and the future of work, emphasizing the importance of critical thinking and adaptability in an ever-changing landscape. The book is divided into sections that tackle issues like artificial intelligence, globalization, and climate change. Harari encourages readers to reflect on their values and the impact of their choices, urging a deeper understanding of the complexities of contemporary life and the interconnectedness of global societies.