COVID-19 outbreak has become a worldwide pandemic. This book "CO-VI-D: Viruses/Vaccines" provides new and unique approach to the discussion of viruses and vaccines in the recent advent of Corona virus. COVID-19 disease is a novel viral disease that was first identified in Wuhan, China. The World Health Organization (WHO) announced its official name, Coronavirus disease 2019, abbreviated as COVID-19; 'CO' stands for 'Corona', 'VI' stands for 'Virus', and 'D' stands for 'Disease'. Globally, more than 10 million people are reported to be infected by COVID-19 (WHO Coronavirus Disease Dashboard, 2020). Centers for Disease Control and Prevention (CDC, USA, 2020) (provided guidelines on how to reduce the risk of infection. It has been discovered that some people get really very sick and die, whereas to some people nothing happens even though they test positive for the virus. Through this book, we intend to explore etiology, development, and treatment of the COVID-19 disease. The specific topics will give details that could help in understanding symptoms, immunity, worldwide spread and treatments so that we could beat this invisible dangerous beast, the COVID-19.