This book reviews the current knowledge of the globally circulating SARS-CoV-2 variants, highlights their distinct genetic characteristics and associated conformational changes in the viral spike protein, and profoundly discusses the mechanisms of convergent evolution that led to the rise of these mutated strains at different geographic regions during the Covid-19 pandemic. Furthermore, the book explores how these variants do and may impact the efficacy of established neutralizing antibody-based (nAb) vaccines and therapeutics by analysing latest in vivo and in vitro clinical data. Finally, the author discusses ways on how nAb Covid-19 treatment derived immune escape of SARS-CoV-2 could be minimized in the future.