nested compound boolean IIf statements

[Linton]

Hi, I need to construct the following:
IIf([field1]Is Not Null And [field2] Is
Null,"true","false").

I can make it work without the Boolean operator and the
second half of the statement, i.e. IIf([field1] Is Not
Null,"true","false"), but can't with the "And" and the
second logical operation. Is there a way to place
multiple boolean logical operations in an IIf statement?
I'm doing all this in a query, and ultimately need to
build something like the following:

IIf(expression,true,IIf(expression,true,IIf
(expression,true, ......

 

[Les]

IIf([field1] Is Not Null,IIf([field2] Is
Null,"true","false"),"false")