Polaritons in van der Waals (vdW) materials are hybrid light-matter oscillations that arise from various physical phenomena, including plasmons in graphene, phonon polaritons in boron nitride, exciton polaritons in dichalcogenides, and magnon polaritons in magnetic materials. These polaritons exhibit strong confinement due to the unique anisotropic properties of vdW materials, which have opposite signs of in-plane and out-of-plane permittivities. This allows for efficient polaritonic waveguides and subdiffractional focusing. vdW materials support a wide range of polaritonic modes, including plasmon, phonon, and exciton polaritons, and their properties can be tuned through electrical gating and other methods. The extreme confinement of vdW polaritons enables new optical effects and applications in nanophotonics, quantum optics, and nanomanipulation. Recent advances in near-field imaging and spectroscopy have revealed the rich physics of vdW materials, including their ability to access regions of the dispersion relations of various excitations beyond conventional optics. The study of polaritons in vdW materials is a vibrant area of research with potential applications in quantum technologies, sensing, and optoelectronics.Polaritons in van der Waals (vdW) materials are hybrid light-matter oscillations that arise from various physical phenomena, including plasmons in graphene, phonon polaritons in boron nitride, exciton polaritons in dichalcogenides, and magnon polaritons in magnetic materials. These polaritons exhibit strong confinement due to the unique anisotropic properties of vdW materials, which have opposite signs of in-plane and out-of-plane permittivities. This allows for efficient polaritonic waveguides and subdiffractional focusing. vdW materials support a wide range of polaritonic modes, including plasmon, phonon, and exciton polaritons, and their properties can be tuned through electrical gating and other methods. The extreme confinement of vdW polaritons enables new optical effects and applications in nanophotonics, quantum optics, and nanomanipulation. Recent advances in near-field imaging and spectroscopy have revealed the rich physics of vdW materials, including their ability to access regions of the dispersion relations of various excitations beyond conventional optics. The study of polaritons in vdW materials is a vibrant area of research with potential applications in quantum technologies, sensing, and optoelectronics.