The photosphere is essentially a relatively thin boundary layer between two fundamentally different plasma regimes. The solar interior is characterized by high density, high opacity, high $\beta $ and convective instability, whereas the outer solar atmosphere has the opposite properties. The convection in the interior provides the ultimate driving force for all of the dynamic and magnetic structure of the solar atmosphere, yet when we view the photosphere, we can observe only the upper boundary of the convection zone. Instead, we observe primarily its various after-effects: overshoot, wave propagation, and confinement of the magnetic field. These observable phenomena are described with a view toward diagnosing the essential physics above and below the photosphere. The convective modes, granulation and supergranulation, are reviewed briefly; the oscillatory modes are discussed in somewhat more detail. Finally, the magnetic structure of the photosphere is described.