I'm not sure if it will appeal to a large audience, but it absolutely appealed to my bug-loving 8-year-old and her sister, who appreciates a cool idea/invention. I loved how each page felt almost interactive, with arrows pointing to important facts or images. Great facts peppered in throughout (like prehistoric dragonflies' 2-foot wingspan!)
My only negative feedback is that visually it appeals to a younger crowd, maybe 6-10yo, but some of it feels a bit advanced for that age group. The facts/information is geared more towards the 9-12yo crowd. I could see younger kids picking this up and not being able to connect with the information, or on the flip side - older kids avoiding the cute cover + layout, when they'd benefit greatly from the information.
Overall, though, I loved this one. I will likely be purchasing a copy for my kids, even though they've already read this online copy with me.