The paper by N. M. R. Peres, F. Guinea, and A. H. Castro Neto explores the electronic and transport properties of graphene in the presence of localized and extended defects, as well as electron-electron interactions. They analyze how point defects, such as vacancies and impurities, and extended defects, such as edges and grain boundaries, affect the electronic and transport properties of graphene. The authors find that point defects induce a finite elastic lifetime at low energies, enhancing the electronic density of states near the Fermi level. Localized disorder leads to a universal, disorder-independent electrical conductivity at low temperatures, which increases with temperature and shows oscillations in the presence of a magnetic field. The static conductivity increases with temperature and exhibits oscillations in a magnetic field. The graphene magnetic susceptibility is temperature-dependent and increases with the number of defects. Extended defects induce localized states near the Fermi level, leading to self-doping, where charge is transferred between defects and the bulk. The role of electron-electron interactions in controlling self-doping is also discussed. The paper also addresses the integer and fractional quantum Hall effect in graphene, the role of edge states induced by a magnetic field, and the possibility of magnetism in graphene due to short-range electron-electron interactions and disorder. The authors provide a comprehensive study of the electronic properties of graphene in the presence of defects and interactions, making predictions that can be tested experimentally.The paper by N. M. R. Peres, F. Guinea, and A. H. Castro Neto explores the electronic and transport properties of graphene in the presence of localized and extended defects, as well as electron-electron interactions. They analyze how point defects, such as vacancies and impurities, and extended defects, such as edges and grain boundaries, affect the electronic and transport properties of graphene. The authors find that point defects induce a finite elastic lifetime at low energies, enhancing the electronic density of states near the Fermi level. Localized disorder leads to a universal, disorder-independent electrical conductivity at low temperatures, which increases with temperature and shows oscillations in the presence of a magnetic field. The static conductivity increases with temperature and exhibits oscillations in a magnetic field. The graphene magnetic susceptibility is temperature-dependent and increases with the number of defects. Extended defects induce localized states near the Fermi level, leading to self-doping, where charge is transferred between defects and the bulk. The role of electron-electron interactions in controlling self-doping is also discussed. The paper also addresses the integer and fractional quantum Hall effect in graphene, the role of edge states induced by a magnetic field, and the possibility of magnetism in graphene due to short-range electron-electron interactions and disorder. The authors provide a comprehensive study of the electronic properties of graphene in the presence of defects and interactions, making predictions that can be tested experimentally.