The article reviews recent theoretical and experimental advances in the study of ultracold gases of bosonic particles interacting via long-range, anisotropic dipole-dipole interactions, in addition to the short-range, isotropic contact interactions typical of ultracold gases. It emphasizes the unique properties arising from dipolar interactions, from the mean-field regime in dilute Bose-Einstein condensates (BECs) to strongly correlated regimes in dipolar bosons in optical lattices. The review covers the creation of dipolar gases using polar molecules, Rydberg atoms, light-induced dipoles, and magnetic dipoles. It discusses the non-local Gross-Pitaevskii equation for describing dipolar interactions, ground state properties and excitations, dynamics of dipolar gases, non-linear atom optics with dipolar gases, dipolar effects in spinor condensates, and dipolar gases in optical lattices. The review highlights the importance of dipolar interactions in quantum gases, their role in novel physical phenomena, and their potential applications in quantum information and metrology. It also addresses the challenges and opportunities in studying dipolar systems, including the use of Feshbach resonances and demagnetization cooling. The review concludes with an outlook on future directions, including the study of dipolar gases in optical lattices and their potential applications in quantum technologies.The article reviews recent theoretical and experimental advances in the study of ultracold gases of bosonic particles interacting via long-range, anisotropic dipole-dipole interactions, in addition to the short-range, isotropic contact interactions typical of ultracold gases. It emphasizes the unique properties arising from dipolar interactions, from the mean-field regime in dilute Bose-Einstein condensates (BECs) to strongly correlated regimes in dipolar bosons in optical lattices. The review covers the creation of dipolar gases using polar molecules, Rydberg atoms, light-induced dipoles, and magnetic dipoles. It discusses the non-local Gross-Pitaevskii equation for describing dipolar interactions, ground state properties and excitations, dynamics of dipolar gases, non-linear atom optics with dipolar gases, dipolar effects in spinor condensates, and dipolar gases in optical lattices. The review highlights the importance of dipolar interactions in quantum gases, their role in novel physical phenomena, and their potential applications in quantum information and metrology. It also addresses the challenges and opportunities in studying dipolar systems, including the use of Feshbach resonances and demagnetization cooling. The review concludes with an outlook on future directions, including the study of dipolar gases in optical lattices and their potential applications in quantum technologies.