The practice of crowdsourcing provides a very concise, yet very practical, guide to crowdsourcing computing. In computer science, we discuss algorithms, software, hardware, design, and societal issues in computing, among many other topics. The field of crowdsourcing deals with computing from a very different perspective, that is, the part of computing that is actually done by human beings. Such a computing task is called a human intelligence task (HIT). Crowdsourcing, as discussed in the book, is when a task of computing, or at least a part of it, is done by participating humans. We call those participants who take part in a computing task “human computers.” For example, in determining if coins are actually showing an equal probability of heads or tails, one system may ask people to report what they see in an experiment of their own. In this process, the designers of this crowdsourcing computing task would make sure the process of executing this task and its related data collection are well designed so that the results are meaningful and trustworthy. The book systematically describes all aspects of crowdsourcing, including framework, design, algorithms, deployment, data collection, and quality assurance. The book is a very good practical guide for any practitioners who are interested in conducting such a crowdsourcing task. It is also a very good read for anyone who would like to learn about the field. The author discusses the topic and its related issues very concisely. The language used is very easy to understand; no prior expertise is necessary. The author also includes many cartoon-like drawings that make reading more pleasant. And for readers who would like to pursue the topic further, the book provides a comprehensive list of some 260 references in the field.