Book excerpt: : This book provides a comprehensive overview of blockchain technology and its various facets. In Chapter 1, it introduces the concept of blockchain, highlighting its decentralized nature, transparency, and immutability, and explores its historical context and diverse applications in engineering and beyond. Chapter 2 delves into the fundamentals of blockchain architecture, including the structure of blocks, cryptographic keys, consensus mechanisms, mining, and the world of smart contracts and decentralized applications (DApps). Chapter 3 focuses on the structure of a block, emphasizing its role as a foundational unit for securing and recording transactions. Chapter 4 delves deep into the essential role of cryptography in blockchain, covering cryptographic hash functions, public and private keys, mining, elliptic curve cryptography, consensus algorithms, and addressing the potential threat of quantum computing. In Chapter 5, the book explores cryptocurrencies, emphasizing their decentralized nature, transparency, low fees, and global reach, along with their use in various applications, the process of acquiring them, and the significance of cryptocurrency wallets. Chapter 6 introduces Ethereum, highlighting its role as a decentralized computing platform, the Ethereum Virtual Machine, the creation and deployment of smart contracts, and the growing world of DApps and their impact on engineering. Chapter 7 delves into blockchain security, addressing common challenges like 51% attacks, consensus algorithm vulnerabilities, smart contract risks, privacy concerns, wallet security, and the looming quantum computing threat, among others. Lastly, Chapter 8 explores the complex world of regulatory and legal considerations in the realm of cryptocurrencies and blockchain technology, discussing the need for various types of regulations, providing examples from different jurisdictions, and highlighting the challenges of regulating a global, ever-evolving industry. Throughout the book, the critical balance between regulation and innovation is emphasized, recognizing the potential of blockchain technology while ensuring consumer protection and the integrity of the technology.