Malicious software, better known as malware, has become a central element in not just cybersecurity but daily life. It has played a role in everything from our politics to our economy, to our personal lives. However, it remains a poorly understood and reported subject. This course provides a clear and comprehensive introduction to malware and how to defend against it. Instruction is divided into two modules. The first provides an overview of the history and mechanisms of malware. The second module offers a series of real-world scenarios in which the learner must apply several of the concepts covered in the first module.