  In what has been described as the fourth age of Quantum Chemistry,
variational nuclear motion programs are now routinely being used to obtain the
vibration-rotation levels and corresponding wavefunctions of small molecules to
the sort of high accuracy demanded by comparison with spectroscopy. In this
perspective I will discuss the current state-of-the-art which, for example,
shows that these calculations are increasingly competitive with measurements
or, indeed, replacing them and thus becoming the primary source of data on key
processes. To achieve this accuracy {\it ab initio} requires consideration
small effects, routinely ignored in standard calculations, such those due to
quantum electrodynamics (QED). Variational calculations are being used to
generate huge list of transitions which provide the input for models of
radiative transport through hot atmospheres and to fill in or even replace
measured transition intensities. Future prospects such as study of molecular
states near dissociation, which can provide a link with low-energy chemical
reactions, are discussed.
