Marie Kondo has a number of great books out. Which you want to read first might depend on the type of tidying and organizing you are wishing to do. In her best-seller, "The Life-Changing Magic of Tidying Up: The Japanese Art of Decluttering and Organizing", Marie talks about many organizing tips but the one that got the most attention was how to organize books. While some thought she was encouraging people to toss their books, Konda defended that such was not the case. She said she is just teaching how to organize and sift through them.
If you want to start with a fairly all-inclusive book, the"The Life-Changing Magic of Tidying Up: The Japanese Art of Decluttering and Organizing" would be the best one. It gives a great overall look at how to begin in the art of Japanese decluttering and is quite informative. It has helped many readers get organized.
Oh, read all of Marie Kondo's books, why not? You have everything to gain. However, if you can only BUY to KEEP one of them, then make it The Life-Changing Magic of Tidying Up: The Japanese Art of Decluttering and Organizing.
Unlike Fifty Shades of Grey, you won't find it left behind in hotel rooms or filling the shelves of charity stores. People normally state "I NEED THIS" and claim that it has changed their lives.