  This paper deals with the theory of structure, stability, robustness, and
stabilization for an appealing class of nonlinear systems which arises in the
analysis of chemical networks.
  The results given here extend, but are also heavily based upon, certain
previous work by Feinberg, Horn, and Jackson, of which a self-contained and
streamlined exposition is included.
  The theoretical conclusions are illustrated through an application to the
kinetic proofreading model proposed by McKeithan for T-cell receptor signal
transduction. (Update includes, among other topics, remarks on extensions to
certain systems with Michaelis-Menten kinetics.)
