What is the difference between Bitcoin and the various monies used in multiplayer games? Each is defined by software, is created out of nothing, and can have prices comparable to traditional currencies. To a casual observer, they seem much the same.

But there is an important difference in how they’re designed that affects every aspect of their respective systems: whereas game currencies try to stop cheating by reactively banning users suspected of abuse, Bitcoin proactively prevents various types of cheating by making them impossible, impractical, or less profitable than honest behavior.

Grokking Bitcoin describes exactly how Bitcoin accomplishes that. As you learn about hash functions, digital signatures, proof of work, and many other technical concepts, you’ll see over and over that Bitcoin effectively prevents cheating without requiring the global banning of any user.

The book then demonstrates the many benefits of this key feature. As you learn about addresses, wallets, miners, and nodes, you’ll discover that if no one can cheat effectively, it’s safe to allow everyone to participate in every part of the protocol, leaving no one in a trusted position of authority over the system. And with no one holding a trusted position, there’s no need for identities in the first place. Grokking Bitcoin goes on to show how it’s possible for anyone to use the public Bitcoin blockchain with a degree of privacy.

A decentralized system that doesn’t use identities or depend on trust is quite different from the everyday systems with which most of us are familiar. Author Kalle Rosenbaum turns this liability into an asset by starting the explanation of each part of Bitcoin using a centralized, trusted, or identity-dependent system that any reader can intuitively understand. He then transforms that basic system step-by-step into the decentralized, trustless, and pseudonymous system implemented in Bitcoin. With each step filled with clear explanations and many excellent illustrations, even the most highly technical topic is made accessible to the interested layperson.

Bitcoin needs books like Grokking Bitcoin, but it also needs an active group of users who read those books and come to understand the technical principles on which Bitcoin is built. During these early days of what I hope will be the long history of Bitcoin, users are often asked to evaluate proposed changes to the system—changes that may affect the security and privacy of their bitcoins. Those who have read this book will understand how the system prevents cheating and will be able to help ensure that future changes preserve that essential feature and its many benefits.

—David A. Harding
Contributor to Bitcoin documentation