No idea about Nurturing Heart, but free range:
Basically, if you grew up in the western world (US, Canada, most of western Europe, etc), it's giving our kids the childhood we had, rather than conforming to the push to "hyperparent," ie schedule every minute of the kid's day, watch them constantly, never allow them to be alone or do anything independently, stranger danger, etc. Free ranging is parenting based on reality and reasonable boundaries, as well as education and equipment of the child to deal with reality, rather than parenting out of sensationalised fear and paranoia and simply sheltering them away from the "big mean world."
I think it's more a reactionary thing, for parents who live in the burbs and have seen the decline of community, the absurd paranoia, the crazy security measures, the stress parents put on kids.
I'm pretty free range. We live in a tiny town. We know almost everyone who's year-round. I'm a little less free range in the summer simply because of the influx of tourists right near our house at the beach. In any case, my two oldest (and 8yr old and 6yr old, if they're together) have a 2km/20 minute's walk boundary from our house. Which is pretty much the entire town, LOL. Lots of parents around here are more free range by default. Kids are out and about and play with each other like they did when I was young. Kids aren't really hyperparented en masse here (maybe we just lack stuff for them to schedule them into every second of every day), but they sure were back in the UK. I guess time hasn't caught up with our town and parents don't really have any fears that cause them to not let their kids out.
