I just cannot solve this one. Any help you can give is much appreciated......

There are 12 sheets labled Jan, Feb Mar etc. Each sheet has the following

Col A - Name
Col C - Data to be summed

On a summary sheet I would like to able to do the following : -

For a particular month, say May, and a particular Name, sum all of the Col C
data
for the preceeding months (in this case from worksheets Jan to April).

Thanks in advance

Kevin