I started collecting hard cover gardening books before the internet was what it is today. These books have given me endless pleasure and ideas over the years. The internet can't be beat for rapidly honing in on specific information, but I still love to curl up with my hard cover gardening books. Now with Amazon, as you mentioned, you can find them at bargain prices. I don't know how I've missed Christopher Lloyd all these years and will probably get 'The Cottage Garden" and a few others that look interesting. I have a big reference picture book on Irises, but can't remember the name. I remember that I got it years ago at a book store that was a short walk from the surgery center where I had taken my brother in law for knee surgery. It was in/out ACL repair, but it was most of the day, and perusing that Iris book was a good way to spend the waiting time.

Most of the Iris books I've seen are more like catalogs of German Bearded Irs...but this one that I got is more a botanists look at the WHOLE GENUS which is really fascinating. I am hoping to collect different species of Iris as I learn more about them. They've always been one of my fav flowers.

Yeah, getting to know Christopher Lloyd is definitely a treat. I stand in total awe of his gardens at Great Dixter...of course, they take crews to keep going, but I always get ideas looking at pics of them.

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/