Got me curious about my Iris book - this is the one I have. It has more than just the bearded, lots of color photographs and some information, but probably not as detailed in the botanist look. I have been trying and collecting all kinds of iris - love them all. Hard to say what kind are my favorite, but maybe it would be the Japanese iris.
https://www.amazon.com/dp/0881927309/
Last winter, or maybe it was the winter before, I got the bright idea of adding a Pinterest board with pins of all the gardening books in my library. Only got maybe a quarter of them in there - reminds me of yet another good project to finish up during these winter months. I don't want to work anymore - I just want to garden and do garden related activities LOL. Sounds like you love gardening books as much as I do - maybe you might see something that sparks your interest with some of the books that I've found over the years - a lot of them came from Amazon bargain buys.
https://www.amazon.com/dp/0881927309/
