The monograph’s subject matter centres on cryptocurrencies, an instrument which aspires to be a modern form of money, and on its place in the world economy, payments systems and financial markets. Special attention is paid to the principles of their usage in Initial Coin Offerings (ICOs), one of the most important areas of their application. The aim of the work is the identification of the economic essence of cryptocurrencies. This includes their functions in settlement systems and as financial instruments, an indication of their role in crowdfunding, as well as the characterisation of the mechanism of the ICO and its core rules. The ICO market is becoming more and more popular among investors and companies seeking to increase or raise capital. The analysis of the cases included in the book shows the importance of a well-prepared white paper, the primary document which contains all the information linked with the project.