In functional terms, a reference manager is a program that allows you to collect, organize, and cite reference materials (e.g., books, journal articles, websites). It has become an invaluable tool for anyone engaged in modern academic writing. Through my career I've used a variety of reference managers, and their functionality is an integral part of my work flow which involves reading academic material, collaborating with other authors, and writing across a variety of platforms such as LaTeX, Authorea, and Libre Office.