The use of polymeric nanocomposites (PNCs) as matrix in fabric reinforced composites leads to a novel concept of fabric reinforced nanocomposite-matrix composite (FRNC). This book explains the development of polyetherimide (PEI)/nanoclay nanocomposites by specially developed vibration casting method. These nanocomposites are fabricated with varying content of nanoclay in PEI. It further explains the development of FRNC using compression moulding technology. FRNC is developed by reinforcing E-glass fabric in nanocomposite matrix. The nanocomposite with optimum mechanical, thermal and dielectric properties along with the least transmission loss and reflection loss is chosen as matrix for FRNC. The mechanical properties, thermal properties and electromagnetic transparency of the FRNC are found to be excellent. The structure-property relationship and various mechanisms involved are also discussed. FRNC has immense potential to be used for specialized applications in aerospace, defence, automotives, pressure vessels, etc.