This paper concerns propagation of transient electromagnetic waves in later
ally discontinuous dispersive media. The approach, used here, employs a com
ponent decomposition of all fields. Specifically, the propagation operator
that maps a transverse field on one plane to another plane is specified. Ex
pansion of this mapping near the wave front determines the precursor or for
erunner of the problem. (C) 2001 Elsevier Science B.V. All rights reserved.