Can you use a wildcard in the where clause of a select statement?

if thisform.cToShow = "All"
    lcCatToShow = ""        &&>>> This is where I want a wildcard
   else
    lcCatToShow = thisform.cToShow  && Or a specific one
endif

SELECT a.company, a.conname, a.ab_id ;
	from AddressBook a;
	inner join CatLink on a.ab_id == CatLink.ab_id ;

	where obsolete = .f. ;
	and CatLink.Catagory == lcCatToShow ;

	ORDER by &lcDisplayOrder  ;
	into cursor DisplayNames

I tried the "" and got nothing.

TIA