In this paper we consider, within the framework of the linear theory o
f elasticity, the problem of circularly cylindrical and plane layered
media under antiplane deformations. The layers are, in the first insta
nce, coaxial cylinders of annular cross-sections with arbitrary radii
and different shear moduli. The number of layers is arbitrary and the
system is subjected to arbitrary loading (singularities). The solution
is derived by applying the heterogenization technique recently develo
ped by the authors. Our formulation reduces the problem to solving lin
ear functional equations and leads naturally to a group structure on t
he set t of real numbers such that - 1 < t < 1. This allows us to writ
e down the solution explicitly in terms of the solution of a correspon
ding homogeneous problem subjected to the same loading. In the course
of these developments, it is discovered that certain types of inclusio
ns do not disturb a uniform longitudinal shear. That these inclusions,
which may be termed ''stealth,'' are important in design and hole rei
nforcements is pointed out. By considering a limiting case of the afor
ementioned governing equations, the solution of plane layered media ca
n be obtained. Alternatively, our formulation leads, in the case of pl
ane layered media, to linear functional equations of the finite differ
ence type which can be solved by several standard techniques.