Information technology, practical and technical computer science are key terms of innovation. This book provides an overview and detailed information for reference and further education. For students of computer science, technical computer science, and information technology, it includes many important foundational elements of the necessary basic knowledge. For career changers, the book offers an overview to avoid getting lost in the complexity of new tasks. As practice-oriented authors with industry experience, the authors have focused on the essentials. The new edition has been updated and includes a section on programming: programming microcontrollers, programming in C++, and programming in Java.