In recent years considerable interest has developed in the mathe-
matical analysis of chemically reacting systems both in the absence and
in the presence of diffusion. Earlier work has been limited to simple
problems amenable to closed form solutions, but now the computer permits
the numerical solution of complex systems of nonlinear differ- ential
equations. The numerical approach provides quantitative infor- mation,
but for practical reasons it must be limited to a rather narrow range of
the parameters of the problem. Consequently, it is desirable to obtain
broader qualitative information about the solutions by in- vestigating
from a more fundamental mathematical point of view the structure of the
differential equations. This theoretical approach can actually
complement and guide the computational approach by narrow- ing down
trial and error procedures, pinpointing singularities and suggesting
methods for handling them. The study of the structure of the
differential equations may also clarify some physical principles and
suggest new experiments. A serious limitation ofthe theoretical approach
is that many of the results obtained, such as the sufficient conditions
for the stability of the steady state, turn out to be very conservative.
Thus the theoretical and computational approaches are best used to-
gether for the purpose of understanding, designing, and controlling
chemically reacting systems. The present monograph is intended as a
contribution to the theory of the differential equations describing
chemically reacting systems.