compare 2 columns from 2 dif. worksheet and return a value

[Isa2011]

Hello, How can I compare two columns(text) from two different worksheets and return a value (#) from one of the worksheets(Data), only if both columns/cell information are the same. The returned value goes into a 3rd worksheet? Txs!

[brokenbiscuits]

Something like:

=if('[Book1.xls]Data'!A1='[Book2.xls]Data'!A1,'[Book1.xls]Data'!A1,"")

?