  Various works performed by the present authors in the 1990s are reviewed. The
topics discussed in this paper are mainly related to the time-evolution of the
coherent and the squeezed states of the systems obeying the su(2)- and the
su(1,1)-algebra. The formulations are based on the basic idea of the boson
mapping and the TDHF theory in canonical form. Under the time-dependent
variational procedure for trial states appropriately chosen, the time-evolution
of the systems under investigation is described. Further, it is shown that this
method enables us to obtain the classical counterparts of the original quantal
systems.
