Some of us may be familiar with the standard technique using INDEX, SMALL, etc. which, given a single-column or single-row array, we can use to return a list of only those values which satisfy one or more criteria of our choosing.
In a previous post (see here) I outlined a method which, given a range consisting of more than one column, returned a single column consisting of all non-blank entries from that range. It can easily be verified that the single condition within this formula (i.e. that the entry be non-blank) can be extended to multiple criteria and so, effectively, we now have at our disposable the means with which to generate single-column lists from both one- and two-dimensional arrays.
But can we go one further yet again? “Three-dimensional” is the collective term often applied to those formulas in Excel which are capable of operating over not just single columns or rows, nor yet ranges consisting of multiple columns or rows (two-dimensional), but which also function effectively over multiple worksheets.