Light is a powerful tool of science. The quantum conception of light consisting of particles of discrete energy, or photons, underlies its interaction with matter. For solid materials, this understanding has led to transformational applications both as conventional as sensor and display technologies and as extraordinary as lasers. Despite this ubiquity, advances in materials science continue to reveal nuances in the interaction of light with matter. The emergence of layered two-dimensional materials of atomic-scale thickness presents a new two-dimensional landscape in which to play with the interaction between light and matter. These nanomaterials at the extreme limit of surface-to-volume ratio exhibit rich optical phenomenology such as layer dependent bandgaps and degenerate, but distinct, optically excited states. The unique features of atomically-thin materials suggest that these layered systems can be exploited to achieve new regimes of light-matter interactions. In this presentation, I will discuss photonic dressed states in monolayer semiconductors in which excitations of matter become entwined with the photon field. In particular, I will describe the emergence of spin- polarized half-light, half matter quasiparticles, or exciton-polaritons in transition metal dichalcogenides embedded in photonic microcavities. I will trace these novel photonic dressed states across strong and weak regimes, revealing quantum particles and quantum manipulation and adding to the toolbox for engineering novel applications harnessing the unique properties of low-dimensional nanomaterials.