The Advanced ZCatalog Searching HOW-TO on zope.org covers how to query ZCatalogs for objects within certain ranges of dates, but it only shows how to do it using bobobase_modification_time. Specifically, to grab items modified in the last 14 days, it suggests <dtml-in "Catalog(bobobase_modification_time=_.DateTime(date), bobobase_modification_time_usage='range:min')"> That's all well and good, but it told me nothing about using ranges with other date FieldIndexes in ZCatalog. For example, I have a ZCatalog full of ZClasses with parameter 'date' FieldIndexed. Not expecting this to work, I tried: <dtml-in "Catalog(date=_.DateTime()-30, date_usage='range:min')"> ...and blimey if it didn't work! What's happening here? Does indexing a date create a method called {NAME}_usage? If so, how in the world does it do this? Just curious, Curtis Matthews