Inner Join To Lookup Values Twice?

Folks,

My secnario involves two tables - ObservationRegister, and Person.
ObservationRegister contains most of the "useful" fields, including
the UserID of the person that raised the record, and the UserID of the
person to whom the record was assigned for action. I need to write a
query to return all values in the ObservationRegister record, but
instead of returning the UserIDs, I need to look up the actual name,
by looking up the name and userID in the Person table... doing that
once (for just one of the UserID fields) is easy - a quick inner join
does the job - but I effectively need to join to the Person table
"twice", for different keys....

Help? Please!? :)

Steve