This review discusses the electronic properties of bilayer graphene, focusing on its unique characteristics compared to monolayer graphene. Bilayer graphene consists of two coupled monolayers of carbon atoms, with a honeycomb crystal structure. The electronic properties are described using a tight-binding model that accounts for five key parameters, including interlayer coupling and on-site energies. The effective Hamiltonian for bilayer graphene describes massive chiral quasiparticles with a parabolic dispersion at low energy, unlike the massless chiral quasiparticles in monolayer graphene. The electronic band structure of bilayer graphene is different, with a quadratic dispersion rather than a linear one. The band structure can be tuned by doping or gating, allowing for the creation of a tunable band gap. The electronic properties of bilayer graphene include excellent electrical conductivity, high thermal conductivity, mechanical strength, and transparency. Bilayer graphene has potential applications in electronics, optoelectronics, and energy technologies. The electronic properties of bilayer graphene are influenced by factors such as strain, phonons, and electronic interactions. The review also discusses the integer quantum Hall effect, orbital magnetism, and the influence of strain on electronic properties. The effective two-band Hamiltonian at low energy describes the electronic properties of bilayer graphene, with terms that account for massive chiral electrons, trigonal warping, and electron-hole asymmetry. The review concludes with an overview of electronic interaction effects in bilayer graphene.This review discusses the electronic properties of bilayer graphene, focusing on its unique characteristics compared to monolayer graphene. Bilayer graphene consists of two coupled monolayers of carbon atoms, with a honeycomb crystal structure. The electronic properties are described using a tight-binding model that accounts for five key parameters, including interlayer coupling and on-site energies. The effective Hamiltonian for bilayer graphene describes massive chiral quasiparticles with a parabolic dispersion at low energy, unlike the massless chiral quasiparticles in monolayer graphene. The electronic band structure of bilayer graphene is different, with a quadratic dispersion rather than a linear one. The band structure can be tuned by doping or gating, allowing for the creation of a tunable band gap. The electronic properties of bilayer graphene include excellent electrical conductivity, high thermal conductivity, mechanical strength, and transparency. Bilayer graphene has potential applications in electronics, optoelectronics, and energy technologies. The electronic properties of bilayer graphene are influenced by factors such as strain, phonons, and electronic interactions. The review also discusses the integer quantum Hall effect, orbital magnetism, and the influence of strain on electronic properties. The effective two-band Hamiltonian at low energy describes the electronic properties of bilayer graphene, with terms that account for massive chiral electrons, trigonal warping, and electron-hole asymmetry. The review concludes with an overview of electronic interaction effects in bilayer graphene.