This introduction presents an overview of the key concepts discussed in the subsequent chapters of this book. The book addresses three different topics: Embedded Systems, Real-Time Systems, and Open Source Operating Systems. It presents the basic concepts about processes and synchronization, and it is introduced by a case study represented by a nontrivial application for vision-based control. The book also presents several theoretical results that are useful in practice for building systems which are guaranteed to respond within a maximum, given delay. It progressively extends the model to include facts occurring in real applications, so that the final results can be used in practical applications. The book focuses on deadlock, arguably one of the most important issues that may affect a concurrent application. It introduces the notions of Interprocess Communication (IPC), and it concentrates on the shared memory approach.