  We study the electronic structure of alternating-twist tetralayer graphene,
especially near its magic angle $\theta = 1.75^\circ$, for different AA, AB,
and SP sliding geometries at their middle interface that divides two twisted
bilayer graphenes. This sliding dependence is shown for the bandwidths,
bandgaps, and $K$-valley Chern numbers of the lowest-energy valence and
conduction bands as a function of twist angle and interlayer potential
difference. Our analysis reveals that the AA sliding is most favorable for
narrow bands and gaps, and the AB sliding is most prone to developing finite
valley Chern numbers. We further analyze the linear longitudinal optical
absorptions as a function of photon energy and the absorption map in the
moir\'{e} Brillouin zone for specific transition energies. A self-consistent
Hartree calculation reveals that the AA system's electronic structure is most
sensitive to variations in carrier density.
