Thanks all, for the suggestions ...

Actually, since I did not an index on SeqnoFG, none of the suggestions had much of an effect. Once I added the index, however, this ran much better than any of the alternatives suggested.

Select KTrackTagDetail.* From KTrackTagDetail			;
	Join C_Kits On KTrackTagDetail.Seqno = C_Kits.Seqno ;
	where Not KTrackTagDetail.RecordType Like 'AP%'		;
	;
	union 												;
	;
	Select KTrackTagDetail.* From KTrackTagDetail		;
	Join C_Kits On KTrackTagDetail.SeqnoFG = C_Kits.Seqno ;
	where Not KTrackTagDetail.RecordType Like 'AP%'		;
	;
	into Cursor C_Detail

>The following is very slow, presumably because of my use of IN

Select * From KTrackTagDetail							;
>	where (Seqno In (Select Seqno From C_Kits)			;
>	or SeqnoFG In (Select Seqno From C_Kits))			;
>	and Left (RecordType,2) # 'AP'						;
>	into Cursor C_Detail

>So, how can I speed this up?
>
>Thanks