  In this paper we present a detailed theoretical analysis of the cyclotron
resonance in metals in the magnetic field directed along a normal to the
surface of a sample. We show that this resonance occurs due to local geometry
of the Fermi surface of a metal. When the Fermi surface (FS) includes segments
where its curvature turns zero or diverges, this could give rise to resonance
features in the frequency/magnetic field dependence of the surface impedance or
its derivative with respect to the field. Otherwise the resonance is scarcely
detectable unlike the well-known cyclotron resonance in a parallel magnetic
field. The proposed theory agrees with experimantal results concerning both
convenient and organic metals.
