nPEG is the NanoPhotonics andElectromagnetics Group belonging to the Dipartimento di Elettrotecnica ed Elettronica (DEE) of Politecnico di Bari (Italy). nPEG saw the light thanks to the wit and efforts of Professor Antonella D’Orazio, who has strongly encouraged the interdisciplinary cooperation among professors, researchers and PhD students and undergraduates. nPEG members work on the design, fabrication and characterization of optical and microwave devices, featuring over 20 years of experience. Computational Nanophotonics is a decisive matter of interest in nPEG since it covers the first step in designing and investigation of optical complex devices. The application of the physical theories to the actual problems is made throughout numerical models allowing the fast and accurate prediction of the final performance of active and passive devices. nPEG fixes this activity as a strong point around which starts the efficient design of novel photonic structures. Many analytical and numerical codes have been developed by nPEG, also exploiting parallel computing to solve full vectorial three-dimensional problems. At the same time several commercial codes are used to support the research activities. Post processing and data analysis are also performed in well-established mathematical environments. The main home-made codes, based on different methods such as FDTD, FEM, BPM, MoL, TLM, TMM, have been devoted to the analysis of: 1. Rare-earth doped lasers and amplifiers for optical communication Second-order and third-order nonlinear processes for all-optical networks 2. Lithium niobate components for sensing and optical communication systems 3. Photonic band gap structures for light control, sensing and optical communication systems 4. Plasmonic circuitry for extraordinary optical transmission, light localization and trapping, photovoltaics.