  A unified description of i) classical phase transitions and their remnants in
finite systems and ii) quantum phase transitions is presented. The ensuing
discussion relies on the interplay between, on the one hand, the thermodynamic
concepts of temperature and specific heat and on the other, the quantal ones of
coupling strengths in the Hamiltonian. Our considerations are illustrated in an
exactly solvable model of Plastino and Moszkowski [Il Nuovo Cimento {\bf 47},
470 (1978)].
