I am creating a budget workbook. The first sheet will display totals broken
down by Type and Date as entered on other sheets. So, I want the following
function displayed:

Drawing from the sheet called "B & R Materials," show the Sum from Column L
for items that have Type "BOOK" in Column C and "Jan-07" in hidden Column M.

I can get it to work if I direct it to one cell on "B & R Materials", but
not to apply that to the whole column. This is the formula that works for one
cell:
=IF(AND('B & R Materials'!C4="Book", 'B & R Materials'!M4="Jan-07"),SUM('B &
R Materials'!L4))

If I change C4 to $C:$C, it doesn't work. Why? What am I doing wrong?
Thanks,
S.