I have read a lot of water coloring books. I have a top 5 I would recommend and why.
1. Modern Watercolor Botanicals
This is the most thorough book I have read. Sarah Simon is a phenomenal painter and does an amazing job of making it easy to paint florals.
2. Watercolor with me
There are now 2 of these books. I have done the one pictured above. I loved the instruction and that you paint right on the pages. It is awesome to see your work develop. My only recommendation would be that this book have better paper for painting. The colors are kinda wonky on this paper.
3. Celestial Watercolor
I love this one because I am a big astronomy / zodiac nerd. I love that she does very basic definitions and shows you some amazing pieces. She also breaks down how to paint a few of the beautiful works. I just loved this book.
4. Watercolor bible
This book has everything you could need to know about watercolor. I have learned several new techniques and can't wait to read the flower watercolor bible.
5. Painting people in watercolor
I really like that this book breaks down the human body. I don't have a lot of experience painting or drawing people so I really enjoyed the basic breakdowns in this book. This book is more word-based than picture-based.