My goodness, this is a bit specialised, isn’t it? I think I can honestly say this is the first book I’ve seen on painting butterflies, so in this respect, it is at least unique. A word of caution though: this is an American book and these are American butterflies, so don’t be looking for a Purple Emperor or a Camberwell Beauty (though there is a token European Peacock).
The truth is that this isn’t a book aimed in any way at the general painter but is rather a specific style. If you like the idea, it’s well done and the results are attractive so it’s at least worth a look. The surprising thing is that, although they look like watercolours, the paintings are in fact oils.