This document summarizes the regulations and history around generic drug applications (ANDAs) in the United States. It explains that an ANDA is an application to produce a generic version of an approved drug that is the same in dosage, strength, and use. The document outlines the basic requirements for generic drugs and discusses the historical approval pathways including ANDAs, paper NDAs, and monographs that preceded the modern system established by the Hatch-Waxman Act of 1984. This law standardized the ANDA process and established provisions to balance generic competition with patent protections for brand drugs.