The de Haas-van Alphen effect in the magnetic susceptibility of graphite has been interpreted by applying the susceptibility formula for general bands of Lifschitz and Kosevich to the band model of Slonczewski. The majority electrons and holes are responsible for the two periods of oscillation of the susceptibility. The analysis yields information concerning the band structure: (1) the total band overlap is about 0.03 ev, (2) the energy difference between the two doubly degenerate bands at the corner of the Brillouin zone is about 0.025 ev, (3) ${\gamma }_0$ must be larger than about 1.2 ev, and (4) the relation ${\gamma }_1=0.04\mathrm{}{{\gamma }_0}^2$ holes approximately (where both $\gamma \text{'}\mathrm{s}$ are in ev and correspond to Wallace's notation). Calculated carrier densities are 2.4×${10}^{-5\mathrm{}}$ per atom for electrons and 1.8×${10}^{-5\mathrm{}}$ per atom for holes, in rough agreement with estimates made from galvanomagnetic data. Rough agreement with electron specific-heat data is also obtained.