How do I find items common to two columns in Excel?
 

I have two excel spreadsheets with over 1000 stock tickers each. One has
stocks with high growth-rate attributes, the other is value-oriented
attributes. Oddly, some tickers are on both lists.
I want to find a way to quickly find stocks that are unique to either list,
or more importantly, exist on _both_ lists. I've found a 'back-door' way to
do it, but it's too complex to explain succinctly, and it seems that there
must be a function for this... I just can't find it.