Can you tell me about where you started? We're not an HE family, but I do things with them out of school in areas they're curious about (and areas I think they should be interested in!). I've looked through Amazon and haven't found anything yet, particularly as this is not an area I've studied in any depth so don't have a reference point from which to start; we live abroad so other English Language browsing is limited. My children are 12, 10 and 7 by the way. And thanks!