The high resolution spectrograph of the TNG (SARG) was projected to cover a spectral range from (lambda) equals 0.37 up to 0.9 micrometer, with resolution ranging from R equals 19,000 up to R equals 144,000. The dispersing element of the spectrograph is an R4 echelle grating in Quasi-Littrow mode; the beam size is 100 mm giving an RS product of RS equals 46,000 at order center. Both single object and long slit (up to 30 arcsec) observing modes are possible: in the first case cross-dispersion is provided by means of a selection of four grisms; interference filters are used for the long slit mode. A dioptric camera images the cross dispersed spectra onto a mosaic of two 2048 X 4096 EEV CCDs (pixel size: 13.5 micrometer) allowing complete spectral coverage at all resolving power for (lambda) less than 0.8 micrometer. Confocal image slicers are foreseen for observations at R greater than or equal to 76,000; an absorbing cell for accurate radial velocities is also considered. SARG will be rigidly fixed to one of the arms of the TNG fork by means of an optical table and a special thermally insulating enclosure (temperature of all spectrograph components will be kept constant at a preset value by a distributed active thermal control system). All functions are motorized in order to allow very stable performances and full remote control. The architecture of SARG controls will be constructed around a VME crate linked to the TNG LAN and the instrument Workstation B by a fiber optic link.