I need to sum a range (column) of cells dependant on 3 criteria. I have spent
ages searching on here, but have become more and more confused!!

Sum all Column Q if cells in Column M=B1
and if cells in Column C =V2 and <V3

where V2 and V3 are start and end dates and B1 is a text string and columns
Q,M and C are on a different worksheet to B1, V2, V3 and the actual sumif
formula.

I have tried
=SUM(IF('Conferences
2007'!$M:$M=Totals!$B$1,IF($C:$C=Totals!V2,IF($C: $C<Totals!V3,$Q:$Q,))))

But just get '0'

Any ideas - thanks!