Abstract: Our observed universe is one statistical realization of the fundamental laws of nature enacted on the grandest scale. As observational cosmologists, we survey increasingly large volumes of the universe to help ascertain those laws with improved accuracy and precision. Experiments at the cosmic frontier have demonstrated that measurements of the cosmic expansion history and growth of structure are sensitive to physics beyond the Standard Model, including the nature of dark energy, massive neutrinos, the initial conditions of the Universe (e.g., inflation), and the particle properties of dark matter. Continuing this enterprise, the Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST) will catalog more galaxies and collect precision lightcurves for more supernovae during its first year of science operations in 2024-2025 than all previous cosmic surveys combined. The Rubin Observatory construction project is now actively engaged in system integration, test, and commissioning with engineering "first light" expected in mid-2023. I will discuss the pathway from commissioning to realizing the scientific potential of Rubin Observatory.