I got my DS hooked on Warriors when he was in first grade. He's now in third and is just this week re-reading the Super Editions. I also reached a point where I was desperate to find a replacement, and I got all excited when our librarians posted a "If you like Warriors, you'll like..." note in the Erin Hunter section of our library, but none of those other books stuck like Warriors has. DS and his male friends who are into the series all like cats, so that's part of it, but there's also something about the Clans that appeals to boys. DS talks about the different clans the way he talks about different Pokemon or Skylander "types." At this point, I figure, as long as it's interesting to him, he must be getting something out of it.