A finding aid that systematically describes, in greater or lesser detail, the fonds held in one or more archival institutions. The main types are:

• General guides: describe all the archival fonds held in all institutions of the same institutional type
• Repository guides: describe all the fonds held by one archival institution
• Sectoral guides: describe all archives of a particular type
• Thematic guides: identify only those fonds containing records relating to a particular theme or subject
• Topographical guides: generally intended for internal use, they describe all the fonds held by an institution in the order in which they are located in the repositories.