Like another reviewer, this was the very first Apologia textbook that we used. We actually only did a few chapters of this book, due to my poor planning as a newbie homeschooling mom. I plan to break this one back out and do it again in a couple of years (we're doing Apologia's Anatomy text next year). Even though we started this book a few years ago, my kids still remember a lot of fun facts. It'll be fun to dive back in to this one (we'll start from the beginning again because there's a lot of vocab they need to know) and really get back into it. Pun was totally intended. It's a great book. Prepare to have materials on hand for a lot of dioramas and fun projects outlined in the text.