Use this formula and change the ranges appropriately

=SUMPRODUCT(--(Sheet1!$C$2:$C$10=Sheet2!A1)*--(Sheet1!$B$2:$B$10=Sheet2!A5)*--(Sheet1!$B$2:$B$10<=Sheet2!B5)*Sheet1!$A$2:$A$10)

sheet2-A5 and B5 are the from and to dates.

With regards
Sridhar
"Sean" wrote:

I'm looking for a formula that will do this

Add up all values (in Col A) that have a match (in Col C) to a word
that I hold in SheetB A1, that in addition have a match (in Col B)
that falls between two dates I hold in SheetB A1 & B1

What I'm trying to do is total all Sales Invoices for certain named
customers for each of a 4 week period. My data is in one sheet,
database format, my parameters in SheetB.

Don't wish to use a Pivot Table

Thanks