More good advice and tips (five stars); overly prescriptive method (one and a half stars); worth the read overall (four stars).
Letting Go: The Dao of Decluttering: Create Joy through Decluttering, Minimalism, And a Life of Less by Kate Evans Scott and Melinda K. Bryce is another book which claims to have “the most effective process for decluttering your home,” a process based on “Joy and Purpose” [Kindle location 150]. As its subtitle implies, Letting Go combines two distinct decluttering sub-genres: minimalism and life improvement. At least in my experience, the more severe proponents of a minimalist lifestyle (relative to one’s material possessions) advocate for their approach because it’s the Right Thing To Do: Save the Planet, maintain one’s personal purity, and the like. Less austere proponents tout the personal benefits of a “life with less:” satisfaction, happiness, and other good things. Letting Go falls in this camp and takes it a step further: decluttering, minimalism, and a life of less will create Joy (yes, capital J) in your life, which is as much of a need as “food, water, shelter, sleep, safety, and security” .
It’s worth pointing out that this was the third of five books on decluttering which I read this summer. So by this time, my reading goals had evolved: I was looking new tips and ideas, as well as examples which confirmed what I learned from my ‘1000 things project.’ I never had any interest in following someone’s else method, so by the time I read Letting Go, my patience for prescription was wearing even thinner, and Letting Go lays on the prescription rather thickly — at least as strong as Tidying Up and much worse than SHED Your Stuff. It doesn’t take long for Letting Go to start telling you how to live your life, with an Rx that could have ‘clean your home, cleanse yourself’ on the label. For instance, there’s the assertion that “Your home should be your sanctuary from the hustle and bustle of the outside world. When you walk through your front doors, it should feel like a cleansing breath” . Likewise, “Mindful decluttering is a cleansing process. Once you have cleansed away the superfluous items” , you won’t need to worry about organization. Authors Scott and Bryce tell you what your goal should be instead: organizing? No… “That is not your goal. Your goal is to free yourself of the negative energy surrounding you” . Thus it’s no surprise that Letting Go is similarly prescriptive about smaller decisions as well, such as the number of paper items from your child’s life to keep (a dozen per year is “practical” ) or the number of blankets to have (one; you’ll take better care of it, be more grateful and attract positive energy ). As with Tidying Up, Scott and Bryce also believe that “it is much more effective to clear clutter by category” , that the things you discard can find a New Life , and they also display occasional OCD tendencies such as the prescription to have color-coded place settings for each family member .
Despite its prescriptive tone, Letting Go confirmed some of the insights I gained from my 1000 things project and also offered new tips and advice that resonated with me. Among the insights that echoed my experience were the authors’ observation that clutter which fills your house drains both your physical and mental space . Letting Go also advocates curating your things by taking valued objects out of storage and putting them on display and treating them like prized possessions which honors the memories themselves [644, 666]. The authors also recommend photographing childhood mementos and creating a scrapbook to help let go of the physical version . The dual goals of Joy and Purpose  echo my goals of identifiable purpose or value, although I tend to use a broader range of criteria, for instance comfort and satisfaction among others. Letting Go also asserts the importance of gratitude, although it places more emphasis on generating self-gratitude  rather than receiving gratitude from others.
Even though I don’t believe that decluttering by category is always the most effective method, I do like that Letting Go has more categories for things than Tidying Up, which makes the method a bit easier to tackle. Although the notion of letting clothes “find a New Life with someone” else is a little woo-woo for my liking, it did help inspire me to do another culling of my clothing with this idea in mind.
Letting Go also offers useful insights about the time, energy, and attention costs of our possessions, for instance its description of how a piece of clothing can ‘own’ us:
If it was a popular name brand, you might have had to work five hours or more for that dress…What better activities could you have done with that five hours?
This is precisely how what you own, owns you. That dress owns five hours of your time. If you don’t love it, if it doesn’t bring you Joy, then that’s five hours not very well spent. Look into your closet—How much time is in there? 
Although I believe that the notion of a maximized alternative is a fallacy — we most likely would have spent that time working or loafing or something else less than maximal — I do like the idea of considering how much time and effort we embed into our things, and whether we our energies would be better expended or served in some other way. Letting Go follows a common trend of advocating for “experiences” rather than gifts ; in my opinion, this is also too pat of a response (many experiences require considerable time, resources, or expense), shifting from things to experiences, as well as the idea of purchasing many fewer, higher quality, more valued things, are both useful strategies for building a healthier relationship with our things.
And while I’m not willing to go as far as Letting Go does (as do SHED Your Stuff and Tidying Up) by asserting that clearing the clutter in your physical space will automatically bring you joy, reset your life , or clear your mind so much that “you may be able to finally focus on that dream of starting your own business, or you could become more focused on your studies” , such things can and do happen sometimes, whether you choose to embrace the authors’ prescriptions or not. At the very least, Letting Go does offer useful tips for you to pick and choose as you engage in your own decluttering journey.