  The purpose of this work is to pose and solve the problem to guide a
collection of weakly interacting dynamical systems (agents, particles, etc.) to
a specified terminal distribution. The framework is that of mean-field and of
cooperative games. A terminal cost is used to accomplish the task; we establish
that the map between terminal costs and terminal probability distributions is
onto. Our approach relies on and extends the theory of optimal mass transport
and its generalizations.
