Abstract: Dwarf galaxies are key to unlocking our understanding of structure formation and galaxy evolution. Traditionally defined as galaxies below a mass threshold of ~109 Msun, these small systems preserve the history of the Universe in their stars, gas, and chemical elements. Due to their low-masses, they also provide stringent tests for cosmological simulations. In this talk, I will give an overview of how we are mapping the full baryon cycle of these traditional dwarf galaxies, with an emphasis on providing quantitative benchmarks for the leading cosmological models. In addition, I will show how we are moving to the next frontier in low-mass galaxy research with the discovery and characterization of smaller systems hovering at the brink of what we call a galaxy. The physical properties of these extremely low-mass systems lie below many thresholds from theoretical predictions and allow us to address fundamental questions about structure formation, survival, and evolution.