The mobile Internet is on the rise, and the meta-universe is springing up. The technological innovations emerging in the digital age have dramatically changed the way people live. Nowadays, the Internet has replaced books and classrooms as the primary source of knowledge for modern people. In the face of massive amounts of information and the inherent deferred properties of the Internet, modern people must develop more advanced tools and methods to manage knowledge and process information. Through his personal experience, experience, and keen judgment, Tu Zipei, a pioneering big data thinker and technology writer, stands at the forefront of science and technology and the times to give a clear answer—the Second Brain. The Second Brain is a new tool that has emerged between the individual and the Internet. It is not only a digital replica of our biological brain, an external brain that can be recorded, stored and found at any time, it is also a complement and extension of the human biological brain that can constantly and dynamically integrate and analyze our records, and with the spirituality of algorithms, it can also help us discover and create valuable connections, and push the first brain to generate new ideas. This book not only introduces the concept but also explains the methods, steps, and future outlook for building the Second Brain—a brand-new brain-computer collaborative information organizing method, and a unique set of methods to gain insights into yourself and develop a successful life. This method will break your cognitive boundaries and thinking limits, and will also help those who are constantly struggling in the sea of information overload. In addition, the author explores how the second brain, as a personal legacy, can be continuously passed on and optimized to benefit a hundred generations of future generations and become a family advantage from the perspective of data legacy. The kind of life we will lead depends on the kind of information we have access to throughout our lives and how we use it. Those who possess and master the Second Brain and the way to use it will surely increase the efficiency of their learning and work, generate a steady stream of new ideas, and achieve self-fulfillment and success in the digital age, regardless of their occupations.