  Massive and massless arbitrary integer spin fields propagating in
four-dimensional flat space are studied. The massive and massless fields are
treated by using a light-cone gauge helicity basis formalism. Cubic
cross-interactions between massive and massless fields and cubic interactions
between massive fields are investigated. We introduce a classification of such
cubic interactions and using our classification we build all cubic interaction
vertices. Realization of generators of the Poincare algebra on space of
interacting fields is found. As a by-product, some illustrative examples of
light-cone form for 3-point invariant amplitudes of massive and massless fields
are also discussed.
