Abstract: The quantum chromodynamics (QCD) axion, a possible solution to the Strong CP Problem, and more general axion-like particles, with their intrinsic connection to high-scale theories like Grand Unification and String Theory, represent uniquely well-motivated dark matter candidates. As an ultralight particle, the phenomenology of the axion is fundamentally wave-like, requiring paradigmatically different approaches in the search for dark matter. In this talk, I will describe an ongoing multi-pronged search effort targeting the discovery of the axion through precision measurement with the ABRACADABRA and DMRadio detectors in conjunction with observation of extreme astrophysical systems that may generate smoking-gun signals of their interactions with axions. I will then show how state-of-the-art techniques in high-performance computing can be applied to simulate the nonlinear processes that generate axions in the early universe, leading to sharp predictions of the QCD axion mass and shedding light on the dynamics and observable signals associated with networks of topological defects.