Here is what I would like a formula to do???

I have two workbooks- I will place the formula only in one and extract
data/info. from the other.

What I want the formula to do is...
I want it to search through a column of product codes from the other
workbook (numbers, e.g. 21, 22) and when the desired code (let's say 21) is
detected. I want it to return the information (text info) from a different
column (I.E. transaction description) but the same row as the desired result
(21).

I have been messing with Vlookups and have had no luck. I'm thinking I
might need a nested if formula???

Any help would be awesome.