This article reviews recent theoretical and experimental advances in the study of ultracold gases composed of bosonic particles interacting via long-range, anisotropic dipole-dipole interactions, in addition to the short-range, isotropic contact interactions typically present in ultracold gases. The specific properties emerging from the dipolar interaction are emphasized, from the mean-field regime valid for dilute Bose-Einstein condensates to the strongly correlated regimes reached for dipolar bosons in optical lattices. The review covers various aspects, including the properties of the dipole-dipole interaction, the creation of dipolar gases using polar molecules, Rydberg atoms, light-induced dipoles, and magnetic dipoles, the non-local Gross-Pitaevskii equation, ground state properties and excitations, dynamics of a dipolar gas, non-linear atom optics with dipolar gases, dipolar effects in spinor condensates, and strongly correlated systems in optical lattices. The article also discusses the tuning of the dipole-dipole interaction, the creation of dipolar gases, and the experimental techniques used to achieve Bose-Einstein condensation of specific atomic species, such as Chromium. The review highlights the unique features of dipolar interactions, such as their long-range and anisotropic nature, and their impact on the physical properties of quantum gases.This article reviews recent theoretical and experimental advances in the study of ultracold gases composed of bosonic particles interacting via long-range, anisotropic dipole-dipole interactions, in addition to the short-range, isotropic contact interactions typically present in ultracold gases. The specific properties emerging from the dipolar interaction are emphasized, from the mean-field regime valid for dilute Bose-Einstein condensates to the strongly correlated regimes reached for dipolar bosons in optical lattices. The review covers various aspects, including the properties of the dipole-dipole interaction, the creation of dipolar gases using polar molecules, Rydberg atoms, light-induced dipoles, and magnetic dipoles, the non-local Gross-Pitaevskii equation, ground state properties and excitations, dynamics of a dipolar gas, non-linear atom optics with dipolar gases, dipolar effects in spinor condensates, and strongly correlated systems in optical lattices. The article also discusses the tuning of the dipole-dipole interaction, the creation of dipolar gases, and the experimental techniques used to achieve Bose-Einstein condensation of specific atomic species, such as Chromium. The review highlights the unique features of dipolar interactions, such as their long-range and anisotropic nature, and their impact on the physical properties of quantum gases.