The TNG (Telescopio Nazionale Galileo), built as a joint effort of the Italian astronomical community under the coordination of the Observatory of Padua, is a 3.5 meter telescope which will be operating at La Palma at the end of 1996 . While optically and mechanically TNG can be considered as basically derived from ESO's NTT, its design from the instruments and control point of view is new and original. The mode of operation for TNG [21,22] will be based on an end-to-end model, and on assisted observing, with the possibility of flexible scheduling.
The instrumentation plan  currently includes an optical imager (OIG), an infrared imager and spectrograph (GIRIS), a low-resolution spectrograph (LRS), a high dispersion spectrograph (SARG). An adaptive optics system will be available; furthermore, a seeing monitor (DIMM) and a meteo station are currently being implemented.
One of TNG's most advanced features is the telescope and instruments control environment, which is tightly linked to the data handling and archiving mechanism. All instruments and sources of auxiliary information are managed by two software environments: GATE (GAlileo Telescope Environment) at a lower (VME) level, and WSS (Workstation Software System ) at a higher level. This scheme allows all data to follow a predefined path, where information is handled and stored homogeneously, and the integrity and completeness of data are preserved. At a different level, a user interface based on X-Windows (TUI ) allows the observer to control telescope and instruments from a standard Unix workstation.
The information system a user will want to access while observing at the TNG will be composite: the above-mentioned user interface must allow access not only to the control system of telescope and instruments, but also to all the information needed to guide the user through a correct observing session. This means an efficient help system, but also access to archived data, namely technical information, data on trend analysis, seeing and meteo data, calibration frames for specific instrument modes and/or telescope status, etc. This information needs to be provided at the telescope; furthermore, access to external sources ( e.g. astronomical catalogues, data centres, the user's own institute) may be necessary. A browsing mechanism familiar to the user, and possibly homogeneous in accessing both internal and external information, is highly desirable.
In this paper, the implementation of an information retrieval mechanism at the TNG is described, with particular reference to the help system and to the archives at the TNG.