A composite is defined as a combination of two or more materials with a distinguishable interface. The urge to improve the properties of composite materials, has prompted materials scientists to investigate composites with lower and lower reinforcement size, leading to the development of microcomposites and the recent trend in composite research is nanocomposites (with nanometer scale reinforcements). Polymer matrix composite (PMC) can be processed at a much lower temperature, compared to composites with other types of matrix. Depending on the types of polymer matrices, PMC are classified as thermosetting composites and thermoplastic composites. In this present review, thermosetting composites with epoxy matrices will be discussed in detail. Over the last three decades, the use of PMC, has increased tremendously and this dramatic growth is expected to continue in the future. The composites possess many useful properties such as high specific stiffness and strength, dimensional stability, adequate electrical properties and excellent corrosion resistance. The implications are easy transportability, high payload for vehicle, low stress for rotating parts, high ranges for rockets and missiles, which make them attractive for both the civil and defense applications. The composite industry is currently dominated by thermosetting resins namely epoxy, vinyl ester, unsaturated polyester, phenolic, polyimides, cyanate ester etc. This is because of their availability, relative ease of processing, lower cost of capital equipment for processing and low material cost. Topics covered include:Thermosetting Composites,Epoxy Resins,Impact Resistant Epoxy Composites,Modification of Epoxy Matrix,Nanoreinforcement of Epoxy,Simultaneous Nanoreinforcement and Toughening,Fire Retardant Epoxy Composites,Fire Retardant Resin Composition.This review will be of interest to anyone who manufactures or plans to use epoxy composites. This detailed and state-of-the-art review is supported by an indexed section containing approximately 300 key references and abstracts selected from the Polymer Library.