This book is a guide to information on infectious diseases that have either lately appeared for the first time in a population or have recently rapidly increased in incidence such as COVID-19, Ebola, Lassa Fever, MERS, Rift Valley Fever, and Zika virus. Articles avoid medical jargon and use language that laypersons can understand while still providing authoritative, balanced information that addresses pathogens that are causing and threaten to cause significant health crises.