If the first 3 books weren’t grouped together, I wouldn’t have continued this series; it’s fairly simple at the beginning and the progression arc line wouldn’t have been enough to carry my interest. Also, the target age group is probably 12-20 and I’m in my 30’s. But, because the books ARE grouped together, Chrysalis represents a good value and I’d buy again. In fact, book 3 did not contain a hook at the end, and yet I bought Book 4.