  In this paper, we study the composition operators on an algebra of Dirichlet
series, the analogue of the Wiener algebra of absolutely convergent Taylor
series, which we call the Wiener-Dirichlet algebra. We study the connection
between the properties of the operator and of its symbol, with special emphasis
on the compact, automorphic, or isometric character of this operator. We are
led to the intermediate study of algebras of functions of several, or countably
many, complex variables.
