  The long hunt for a symmetric monoidal category of spectra finally ended in
success with the simultaneous discovery of the third author's discovery of
symmetric spectra and the Elmendorf-Kriz-Mandell-May category of S-modules. In
this paper we define and study the model category of symmetric spectra, based
on simplicial sets and topological spaces. We prove that the category of
symmetric spectra is closed symmetric monoidal and that the symmetric monoidal
structure is compatible with the model structure. We prove that the model
category of symmetric spectra is Quillen equivalent to Bousfield and
Friedlander's category of spectra. We show that the monoidal axiom holds, so
that we get model categories of ring spectra and modules over a given ring
spectrum.
