?BLOCKCHAIN TECHNOLOGY? heralds a new social potential and is a disruptive innovation. Discovered as a basis for the cryptocurrency record keeping system, Blockchains are now used as reliable data storage systems universally. Blockchain is a amper-proof, distributed, and decentralized system that can validate and record digital transactions. It is transparent, safe and protects the data integrity. This fantastic technology is used in multiple fields like energy, education, healthcare, finance, voting, land records, intellectual property rights and lot more. This book is about the Fundamentals of Blockchain technology, written by Dr. Kartik Hegadekatti, a senior Civil Servant in Government of India. He has worked extensively on Blockchains and is an authority on it. He has published more than 30 papers internationally and written various books on Blockchains and fintech.