With the acquisition of Hyperion Systems in 2007, Oracle finds itself owning the two most capable OLAP products on the market--Essbase and the OLAP Option to the Oracle Database. While both products fall within the OLAP category and have some similar capabilities, they are different in significant ways. This paper will help the reader understand where these products are similar and where they differ. Most importantly, it will help the reader architect the Oracle OLAP product that is most appropriate for his or her application.