Abstract
The general properties of M giant and dwarf atmospheres are briefly reviewed, and the problems of modeling are described. The authors show, by means of recently calculated dwarf atmospheres, that molecules play a key role in the equation of state and that their absorption determines in most cases the slope of the spectrum. A comparison of calculated and observed spectra of the M-dwarf system Gliese 866 demonstrates the limitations of present modeling and the need for improved data on molecular equilibria and opactities.
