"This book was written after the one-year cycle of intense experience with the COVID-19 pandemic, caused by a new coronavirus, SARS-CoV-2, with a high level of contamination. Such an event began in December 2019, with the emergence of the first cases of the disease in Wuhan City, Hubei Province/China, and within a few months ravaged the world, with towering numbers of infected, critically ill patients, and deaths. More than a year after the beginning of the pandemic, which has led to the collapse of health systems, economy, education and social assistance, among others, in several countries, we are still fighting against new waves of contamination produced by the emergence of virus variants. The outlook is still very critical; in some countries the second and third waves of high levels of contamiintroduction nation have caused more deaths than the first, as is the case in Brazil. In our country, vaccines have finally been approved. Vaccination began in January 2021 for priority groups, but the lack of information, political disagreements, and the denial of science have compromised."