What is blockchain? Certainly, with the huge hype around it, you must have heard or come across this question—it might be even the reason why you are reading this book. Let's discover, in this first chapter from a developer's standpoint, what's behind the hype.

As you might know, blockchain is an emerging technology that has the potential to dramatically revolutionize many different fields. This potential is primarily based on its ability to offer people a trustworthy channel to transfer value or real assets (tokenization) over the internet.

Blockchain has the capacity to move us from the internet of information to the internet of value, potentially breaking our existing financial systems.

Blockchain is in many ways a revolution, similar to the internet when it was conceived—certainly not a passing trend. The reason for this is that it presents a solution to a previously unsolved financial dilemma. For the first time in history, we are able to establish trust within trustless environments (such as the internet), without relying on an authority. As a result, some refer to blockchain as a trust machine.

The potential impact of blockchain is huge—it goes far beyond the mere decentralization of the financial sector. In fact, its ability to circumvent intermediaries opens the door to redefine almost every field revolving around technology—even the internet—pushing us toward a peer-to-peer world.

Through this short introduction, I am trying to give you a foretaste of the importance of our topic, and to confirm that your choice to learn about the technology is timely. As the book's name suggests, the approach we will be following throughout this book is to build concrete blockchain projects, instead of laying out abstract concepts.

Nonetheless, in spite of its less technical nature, the prime objective of this introductory chapter is to provide you with the necessary background to build the various projects presented in this book.

In this chapter, we will cover the following topics:

• What cryptocurrency is
• What blockchain is
• How to send and receive bitcoins
• How to store data into a bitcoin blockchain using JavaScript
• An overview of blockchain types

However, this chapter doesn't intend to cover:

• The underlying cryptography
• Cryptocurrency trading

In this chapter, the first part will introduce basic concepts. The second part will be practical, and we will discover how to interact with the blockchain, using the famous Hello World example to get you started.