  In this work we present spectroscopic observations centered in the spectral
lines most widely used as optical indicators of chromospheric activity
(H{alpha}, H{beta}, Ca II H & K, and He I D{3}) in a sample of F, G, K and M
chromospherically inactive stars. The spectra have been obtained with the aim
of providing a library of high and mid-resolution spectra to be used in the
application of the spectral subtraction technique to obtain the
active-chromosphere contribution to these lines in chromospherically active
single and binary stars. This library can also be used for spectral
classification purposes. A digital version with all the spectra is available
via ftp and the World Wide Web (WWW) in both ASCII and FITS formats
