>>4210993Everyone focuses on Mucha, but art nouveau had a lot of artists working in that genre - highly recommend diving deeper. I started with this book - great overall look at the whole era, including mucha. And, this book is really nice - great print quality, large format, the kind of book they just don't make anymore. It's long out of print, but I've seen it pop up used.
It's on my list of projects, to make an ebook out of it, because books like this shouldn't be forgotten.