Small Stakes No-Limit Hold'em

On page 152, a 64/3 raises to $4 UTG and you 3bet with J7s to isolate.  If he is raising 3% of his hands does that mean he is raising 3% of the 64% of hands that he limps with or is he raising 3% of all possible hands?  If it's 3% of all possible hands, why would you isolate with a weak hand?

Great points are brought up here. Ed, this might be a big leak in my game, but here's what I generally do:

Even if the player is a 60/3, I'm taking absolutely opportunity to play a pot in position with this player. One thing I look at is their Fold to CB percentage on all street. If it's fairly high, regardless of my hand, I'm going after them. Like you mentioned, their 3% doesn't mean it's the top 3% (I recommend Flopzilla for those who want to get better with range percentages).

These players typically don't last long at the table; all the solid players are eyeballing this player. If I don't take it, someone else will. The exception (would like your thought on this Ed) is at game like 3/6 5/10.  I tend to me more careful on isolating bad players. They seem to pickup on the fact you're isolating and I find myself facing all kinds of raises, especially the later in position I do it in.