Easy lookup question - I.R.Stupid

This should be an easy question, and I should really just know this but I can't remember/find out to do this. I want to lookup and sum in an array.

Example is attached. I want to add all data in column D per agent (who are named in column A) in the second sheet.

There should be a simple formula for this, right? I can't seem to find it in the help though

Hopes this makes sense!

There is no sheet attached, but this formula should work:

=SUMIF(A1:A50,"Agent_NAME",D1:D50)

just adjust ur array

Works like a charm, thx