We present a library of Utrecht echelle spectrograph (UES) observations of a sample of F, G, K and M field dwarf stars covering the spectral range from 4800 Angstroms to 10600 Angstroms with a resolution of 55000. These spectra include some of the spectral lines most widely used as optical and near-infrared indicators of chromospheric activity such as Hβ , Mg i b triplet, Na i D1, D2, He i D3, Hα , and Ca ii IRT lines, as well as a large number of photospheric lines which can also be affected by chromospheric activity. The spectra have been compiled with the aim of providing a set of standards observed at high-resolution 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. Based on observations made with the William Herschel Telescope operated on the island of La Palma by the Isaac Newton Group at the Spanish Observatorio del Roque de Los Muchachos of the Instituto de Astrof\'{i