The living cell is a miniature, self-reproducing, biochemical machine. Like
all machines, it has a power supply, a set of working components that carr
y out its necessary tasks, and control systems that ensure the proper coord
ination of these tasks. In this Special Issue, we focus on the molecular re
gulatory systems that control cell metabolism, gene expression, environment
al responses, development, and reproduction. As for the control systems in
human-engineered machines, these regulatory networks can be described by no
nlinear dynamical equations, for example, ordinary differential equations,
reaction-diffusion equations, stochastic differential equations, or cellula
r automata. The articles collected here illustrate (i) a range of theoretic
al problems presented by modern concepts of cellular regulation, (ii) some
strategies for converting molecular mechanisms into dynamical systems, (iii
) some useful mathematical tools for analyzing and simulating these systems
, and (iv) the sort of results that derive from serious interplay between t
heory and experiment. (C) 2001 American Institute of Physics.