Over the past few years or decades, humanity has been through multiple infectious diseases, whether it be Ebola or the latest pandemic of COVID-19. Infectious diseases aren’t anything new. But, we cannot deny the fact that, with increased and freer movement of humans over this mighty Earth, infectious diseases are spreading and taking up new forms on a regular basis. With these newer forms, many diseases which have historically been known to affect a single organ system, have diversified and now attack multiple organ systems. All of these increase the burden to humankind and to the healthcare ecosystem of the world as a whole. In this course, we will discuss everything about infectious diseases, their various types, presenting complaints, etc. We will also discuss the related topic of Bioterrorism in this course.