This book provides the reader with a hands-on knowledge about real-time operating systems and their possible application in the embedded system domain. Besides analyzing in detail one or a few realistic case studies, and using them as running examples while introducing the theoretical material, the book will also discuss open-source operating systems, which are starting to gain popularity in this field, but are often misunderstood because they lack comprehensive support in the scientific literature. Together, the topics covered by the book will make the average embedded system designer, without significant previous experience with real-time operating system, to understand what are their benefits and weak point and the decide whether it may be worth adopting one of them in his/her next project instead of relying on more traditional, but less powerful, techniques.