The Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has probably been the most important disease to emerge in the 21st century. This viral zoonotic disease has been a significant cause of morbidity and mortality worldwide, but with a higher impact in low- and middle-income countries of Africa, Asia, and Latin America. Up to December 4, 2022, more than 645, 195, 564 cases had been reported globally, with 6, 640, 845 deaths, and more than 13, 054, 668, 703 doses of a vaccine had been given. Research has been of the utmost importance in the COVID-19 crisis: a great deal of knowledge was gathered between December 2019 and December 2022. Appropriate evidence-based management and the development of safe and effective vaccines have been key to controlling the virus. This book presents a selection of the last two years' learning from research and clinical practice concerning SARS-CoV-2/COVID-19.