  We discuss the existence of monodromies associated with the singular points
of the eigenvalue problem for the Rabi model. The complete control of the full
monodromy data requires the taming of the Stokes phenomenon associated with the
unique irregular singular point. The monodromy data, in particular the
composite monodromy, are written in terms of the parameters of the model via
the isomonodromy method and the tau-function of the Painlev\'e V. These data
provide a systematic way to obtain the quantized spectrum of the Rabi model.
