  We revisit the problem of interactions of higher-spin fields in flat space.
We argue that all no-go theorems can be avoided by the light-cone approach,
which results in more interaction vertices as compared to the usual covariant
approaches. It is stressed that there exist two-derivative gravitational
couplings of higher-spin fields. We show that some reincarnation of the
equivalence principle still holds for higher-spin fields - the strength of
gravitational interaction does not depend on spin. Moreover, it follows from
the results by Metsaev that there exists a complete chiral higher-spin theory
in four dimensions. We give a simple derivation of this theory and show that
the four-point scattering amplitude vanishes. Also, we reconstruct the quartic
vertex of the scalar field in the unitary higher-spin theory, which turns out
to be perturbatively local.
