I'm interested in hearing about uses of the <extension> element in MODS. I copied out a fairly recent exchange, because this is the type of extension I am interested in. I also found a declaration of MODS extension for dates that Oxford University uses at http://www2.odl.ox.ac.uk/data/aaaaaa/schema/odl.xsd Are there more examples out there? Ruth Ruth A. Bogan Head, Database and Catalog Portal Management Rutgers University Libraries 47 Davidson Rd., Busch Campus Piscataway NJ 08854 Rebecca Guenther to Jenn Riley: 20041104 Another alternative might be to use the <extension> element, where you can use elements from another schema. Using that you could point to the namespace for MIX and then use the MIX element. Here is what it would like like: <extension><CameraCaptureSettings xmls: "http://www.loc.gov/standards/mix/mix.xsd"> then you would parse the data into its appropriate subelements as detailed in MIX. (see: http://www.loc.gov/standards/mix/mix.xsd or the example at: http://www.loc.gov/standards/mix/instances/mix_test.xml) Another alternative if you are just using this locally is to use the <extension> element with your own local element, e.g. <extension><cameraSettings>100 f 4.5 TL</cameraSettings> The intent of extension is to either use a local element or bring in one from another namespace. If the latter, including the namespace allows it to validate against that other schema. If you just use a local element, it doesn't validate the data under it.