  Essential properties of multilayer graphenes are diversified by the number of
layers and the stacking configurations. For an $N$-layer system, Landau levels
are divided into $N$ groups, with each identified by a dominant sublattice
associated with the stacking configuration. We focus on the main
characteristics of Landau levels, including the degeneracy, wave functions,
quantum numbers, onset energies, field-dependent energy spectra,
semiconductor-metal transitions, and crossing patterns, which are reflected in
the magneto-optical spectroscopy, scanning tunneling spectroscopy, and quantum
transport experiments. The Landau levels in AA-stacked graphene are responsible
for multiple Dirac cones, while in AB-stacked graphene the Dirac properties
depend on the number of graphene layers, and in ABC-stacked graphene the
low-lying levels are related to surface states. The Landau-level mixing leads
to anticrossings patterns in energy spectra, which are seen for intergroup
Landau levels in AB-stacked graphene, while in particular, a formation of both
intergroup and intragroup anticrossings is observed in ABC-stacked graphene.
The aforementioned magneto-electronic properties lead to diverse optical
spectra, plasma spectra, and transport properties when the stacking order and
the number of layers are varied. The calculations are in agreement with optical
and transport experiments, and novel features that have not yet been verified
experimentally are presented.
