Thanks to both Michael R. and Mike F. for the *very* helpful clarification. As I understand it then, the c0# element is for sections of the finding aid, while the did element is for describing the actual items (letters, etc), and container/physloc/physdesc are used as needed to describe the physical arrangment of the items. The next problem I'm encountering is that one can only have a single did within a c0#. This seems counterintuitive since a section of a finding aid (e.g. correspondence) might have several actual data items in it (e.g. correspondence A, correspondence B, etc). I'm working now on an example of such a finding aid and so far this is what I've come up with (below). The c0# is given a title since it's a section of the finding aid, then each next lower level c0# does NOT have a title since it's simply there to hold a single did. Does this seem correct? Thanks! Michele <c01><head>Correspondence</head> <did><abstract>Correspondence between John Smith and various parties, organized alphabetically.</abstract></did> <c02> <did> <container type="box">Box 4</container> <container type="folder">Folder 1</container> <unittitle>American Heart Association</unittitle> </did> </c02> <c02> <did> <container type="box">Box 4</container> <container type="folder">Folder 2</container> <unittitle>Anthony, John</unittitle> </did> </c02> <c02> <did> <container type="box">Box 4</container> <container type="folder">Folder 3</container> <unittitle>A (miscellaneous)</unittitle> </did> </c02> </c01> --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.782 / Virus Database: 528 - Release Date: 10/24/2004