missing Contacts on Opportunities

Hi community. 

I'm working on a report of all CONTACTS existing on an open OPP.  Since there is one to many relationship between an OPP and a CONTACT, and we have such cases entered, I expect to see cases where there is more than one CONTACT on an OPP.  But the report only renders one CONTACT per OPP.

Also, there are CONTACTS that are attached to an OPP, but not appearing in my report.  My report has the following columns, in this order:  Opp ID, Opp Name, Contact ID, Contact First Name, Contact Last Name. 

Thanks, Jeff