Speaking of blockchain, someone wondered, “What is mining and how do you keep track of it?” Others want to figure out how to achieve consensus, how to build smart contracts, and still others are confused about whether applications and blockchain can be connected. This book will answer these questions one by one, starting from the underlying technical details of blockchain. First, a systematic analysis of the principles and nature of blockchain technology is provided, starting from the background of its generation and basic concepts, and analyzing in a simple way the profound knowledge of blockchain structure, core algorithms, operation mechanisms and their supporting technologies; second, through the explanation of the features, strengths and weaknesses of blockchain technology, the technology evolution and typical applications are further analyzed.