I picked this up some time after reading Marie Kondo's book, I forget precisely why but presumably it had something to do with the psychology of closets (what your closet says about you, type of thing).
It's okay. It's not great. My recollection of Grant McCracken's _Big Hair_ is that it did a better job than this one on a related topic, and I think that's probably because McCracken took an anthropological perspective (these people have agency and are doing really interesting things to change their lives by changing some physical attribute) versus a psychologist's perspective (these people need help and I will explain to them what their clothing says about them and help them identify what they want to say about themselves and assist in the journey to get from here to there). But it has been long enough since I read _Big Hair_ that it's possible I have rose-tinted memories.
There are a couple elements that really stand out. First, as with McCracken, this is mostly aimed at women. At least McCracken acknowledged this as a problem and explained what he tried to do to get around that and why he thinks he failed. Baumgartner actually has cases in the book involving men -- and immediately applies those lessons to a presumed female readership. That's just taking the easy road. There's no apparent awareness. Second, Baumgartner has the usual failings of someone writing this kind of book. Inevitably, all the fashion advice points women in a particular class/race/socioeconomic direction.
I'm sure she's helpful to her clients; I'm less convinced this book is particularly helpful to anyone. I mean, whenever I read lists of The Only Clothes You Really Need and I don't own any of them, I wonder what the hell is even going on here anyway.