The ISO mission provides a unique opportunity to make very sensitive
 spectroscopic studies over an enormous wavelength range of the nova
 outburst phenomenon. We propose to observe the evolution of four
 novae occurring during the ISO mission, in order to gain important
 information about physical processes in the ejecta, the nuclear
 processed abundances, and dust and molecule formation.

 The discovery rate for Galactic novae is about 6-10 per year, of
 which about one third form optically thick dust shells and one
 third form optically thin dust shells. About one third of all novae
 go through a coronal line emission phase, during which an enormous
 number of ground state infrared fine structure lines from many
 heavy element high ionization stages become very strong, enabling
 very accurate abundances to be derived, free from the uncertainties
 in reddening and electron temperatures and densities that affect
 optical and ultraviolet forbidden-line analyses. The degree of
 ionization varies continuously during this phase and will provide
 important information about the evolution of the underlying remnant.

 The rapid evolution of these transient outbursts provides an
 opportunity to observe the phenomena of molecule and dust formation
 in real time. The progress of molecule formation will be revealed by
 the infrared bands of molecules such as CO and SiO, while the fact
 that all the important dust diagnostic features occur in the IR will
 enable a study of the formation and evolution of various grain species.

 Since nova spectral features undergo rapid temporal evolution, it is
 crucial that sensitive IR spectra covering the widest possible range of
 wavelengths be obtained simultaneously - only ISO provides this
 capability.