The primordial abundance of lithium-7 measured in the atmospheres of the oldest stars (the Spite plateau, a nearly constant Li-7 abundance across a wide range of stellar metallicities) is significantly lower than the abundance predicted by standard Big Bang Nucleosynthesis calculations using the baryon density inferred from Planck CMB observations. The discrepancy amounts to a factor of 3-4, with observed Li-7 abundances appearing too low relative to predictions, suggesting either systematic errors in stellar abundance measurements, unknown nuclear physics, or a fundamental problem with the early-universe nucleosynthesis model itself (Cyburt et al. 2008; Fields et al. 2014).