The COVID-19 pandemic has disrupted every domain of life. Migration and human mobility in general are not exceptions. Since March 2020, researchers, policy makers and many others have channelled their efforts to understand this new coronavirus, its impact and prospects. Many scholars were thinking and writing on the pandemic from its onset and many blog essays quickly appeared. One of the earliest peer-reviewed research articles Sirkeci and Yucesahin (2020) is reproduced here. This article and its focus on mobility and travel data showed that it was possible to predict the spatial spread and concentration of COVID-19 cases. Not only was this finding crucial to developing appropriate policies and strategies to counter the spread of the virus, it reminded us that the pandemic is a social disease and not simply a biological threat. The contributions in this book should be considered in this regard tackling the social and policy aspects as we leave the biological and medical side to the experts.