In my experience, the “Books” category, which is the second overall category in the KonMari method, is often one of the most challenging. When I worked my way through the process myself, I really had to dig deep to confront the reasons I had held onto certain books for so long, especially when I never felt the need to consult them or re-read them. Ultimately, I was able to say goodbye to whole categories of books that were still on my shelves only because I viewed them as part of my identity. Once I realized that I didn’t need the books to prove anything to myself — for example, I no longer needed the books related to my college major when I already have the college degree — I was able to let them go. Of course, once you know which books you’d like to keep, the question of storage and organization comes to the forefront. Here’s an article that contains several useful tips on that topic, including my own: https://www.redfin.com/blog/book-organization-ideas/