You need workarounds to do 3D-lookups. One way is to define a name "Refs"
which refers to the list of references:

="'[CONTROLMASTER_AUGUST_07]"&TEXT(ROW($1:$31),"00")&"-08'!C1:AE999"

Then enter the lookup formula below in the other spreadsheet making sure to
use the same headings as in the table. Extend the formula by selecting the
range e.g. [A2:B999] and choosing Data Table Column Input Cell: A2 OK:

A B
1 No. Value
2 112 =LOOKUP(REPT("z",99),DGET(INDIRECT(Refs),29,A1:A2) &"")
3 234 =TABLE(,A2)
4 456 =TABLE(,A2)
....

"Chrisl147" wrote:

I regularily use VLOOKUP but want to create a LOOKUP that will search all
pages of a workbook and return the required data. I am using a distinct
customer number that will only appear once.