I was absolutely obsessed with the Animorphs series by K.A. Applegate a few years back, and it's still something I think about often. I have like 90% of the books, original and new release as well as the companions, and an entire bookshelf related to Animorphs stuff. I think the series went a lot deeper than the standard children's book level, and the morphing definitely brought up a lot of otherkin feelings with me. (I'm actually questioning Andalite right now.) I highly recommend it. Anyone else a fan? Oh, and I'm naming my dog Tobias. Whoops!