In this dissertation I explore applications of antibodies and alpaca-derived antibody fragments, known as VHHs, to understand severe acute respiratory associated coronavirus (SARS-CoV-2) biology and develop potential therapeutics against COVID-19. Here I study pre-existing SARS-CoV-1 antibodies for cross-reactivity with SARS-CoV-2 and design novel VHHs targeting the viral spike protein (S) and nucleocapsid protein (N). This work significantly advances our understanding of SARS-CoV-2 biology, highlighting the potential for antibody-based therapies and diagnostics against COVID-19 while also emphasizing the role antibodies can have in researching a newly emergent disease.