Introduction. Generic drugs are currently being promoted globally as substitutes for brand-name drugs. The substitution may be generated from the medical provider, the patient, the pharmacist, and/or the third-party payer. The appeal for the substitution is generally the cost. Generic drugs are often substantially cheaper than their brand-name counterparts, thus imparting cost savings to the payer, patient, and the healthcare system. In addition to decreased cost, markers of generic drugs help to increase access. After the patent of an innovative or branded drug has expired, manufacturers are free to provide the market with various competitive genetic formulations of that drug. Although generic and brand-name medicines share the same active ingredient, other characteristics, such as colors and certain excipients, that do not affect the performance, safety, or efficacy of the generic medicine, may be different. This substitution can aften occur unbeknownst to the health-care provider or the patient. Given that the understanding and knowledge base differs by each party involved, whether it is the prescriber, payer, and/or patient, the perceived benefits and risks may also differ. [...]. In this book, we present this history of generic drug development, FDA and European Medicines Agency (EMA) requirements for genetic drug entry, a comparison of generic and brandedf drugs, concerns around generic ophthalmic drugs, the issues of costs of generics and branded drugs, and issues as well as perceptionsregarding the clinical use and acceptance of generic drugs among the patients, prescribers, and pharmacists. In addition to the previous edition, a chapter has been added about biosimilars