How do I construct multiple outer joins?

I need help with a SQL...

I have 3 tables, I've tried:

SELECT Table1.Field1, Table1.Field2, Table2.Field1, Table3.Field1 FROM Table1, Table2,Table3
WHERE Table1.Key1 = Table2.Key1

   AND Table2.Key2(+) = Table3.Key2
   AND Table3.Field1 = 'Criteria' ;

What I need is for it to return Table3.Field1 regardless of whether there is a matching record in Table2. It returns 0 records, I assume because there is no circumstance where "Table1.Key1 = Table2.Key1", since there is no matching record in Table2. Is there a way to write this SQL to do what I need?

--
Randy Harris