SET KEY TO LowestValue RANGE HighestValueSo, you could use SET KEY on a date index and have a range of dates between a start and and end date. I have always used SET KEY because of its speed. It is also better in many circumstances than using SET RELATION TO (when relating cursors) because it actually produces a set of records that have a start and an end, whereas SET RELATION TO only relates a single record in a child cursor to a parent record on the child's FK. So, not only is it better than using SET FILTER, it also is the key to getting a set of records in a VFP navigational cursor (as opposed to a SQL recordset).