Blockchains & smart contracts have made it easy for anyone to create a token with just a few lines of code. They can represent anything from an asset to an access right, like gold, diamonds, a fraction of a Picasso painting or an entry ticket to a concert. Tokens could also be used to reward social media contributions, incentivize the reduction of CO2 emissions, or even ones attention for watching an ad. While it has become easy to create a token, which is collectively managed by a public infrastructure like a blockchain, the understanding of how to apply these tokens is still vague. The book refers to tokens, instead of cryptocurrencies, and explains why the term "token" is the more accurate term, as many of the tokens have never been designed with the purpose to represent a currency. However, since tokens do have similarities to fiat currencies, the role of money as a medium of exchange is analyzed at length in this book. This book gives an overview of the mechanisms and state of blockchain, the socio-economic implications of tokens, and deep dives into selected tokens use cases: Basic Attention Token, Steemit, Token Curated Registries, Purpose Driven Tokens, Stable Tokens, Asset Tokens, Fractional Ownership Tokens, Libra & Calibra (Facebook), and many more.