This four-part seminar is a basic introduction to computer systems, networking, and cybersecurity, including the lower-level protocols and technologies that bind the Internet together. After mastering the basics, we will move on to the layers above, where we will discuss security best practices, encryption, and actual attacks against computer systems and networks. Students need only have a basic knowledge of computer systems, but the class WILL be technical and hands-on. Students will be required to bring computers with them in order to complete in-class exercises throughout the course. This seminar will provide students with a robust understanding of the technical aspects of cybersecurity, preparing them for the full range of cyber- and technology-related courses offered at Harvard Kennedy School. Regardless of their prior background, students will gain technical proficiency that can be applied to a wide variety of careers upon graduation.