  This is an overview of quark flavor physics as presented in a plenary talk at
Lattice 2023. In the first part, I discuss the main processes and lattice-QCD
inputs used to determine the Wolfenstein parameters of the
Cabibbo-Kobayashi-Maskawa matrix. In the second part, I review selected further
processes that are being used to search for physics beyond the Standard Model.
New results presented at Lattice 2023 are referenced throughout, but detailed
discussions are limited to selected work published prior to the conference. QED
corrections, inclusive decays on the lattice, and processes involving hadronic
resonances are not discussed in detail here, as they were covered in other
plenary talks at Lattice 2023 and Lattice 2022.
