The content is based on, I believe, an exhibition of the Lepidoptera illustrations of the Scott sisters, Harriet and Helena. It also springs from a book called Transformations, by Vanessa Finney. The book, as of April 2019, is not available in the US. I bought it in Melbourne, November 2018, which is how I heard about the app.
I would give the content five stars. I'd like to knock off a point on the app itself: on first impression the flaw is that it doesn't fully resize to an iPad screen. But on further examination there are too many cool things going on that I really can't complain. Most importantly, there are the paintings. Then, each page of illustration has a page of informative text, from the original 19th Century publications, written by their father, Walker Scott. Plus, there are documentary videos and a game.
And it's free.