Energy Spectrum of the Hydrogen Atom in a Strong Magnetic Field

We obtain the energy spectrum for the 14 lowest states of the hydrogen atom in a strong magnetic field $B$. Emphasis is placed on values of $B\approx {10}^6-{10}^8$ G, characteristic of those found in magnetic white dwarfs. Our results for the ionization energy of the ground state are significantly better than those of Cohen, Lodenquai, and Ruderman for fields $\lesssim 7\times {10}^{11}$ G.