As an American who has worked many years in the corporate world, I think the reviews criticizing Malloy for being sexist, or promoting unclear rules that vary according to if the supervisor is a woman or a man, are being naive. His excellent and detailed research is clearly explained, and he has no bias whatsoever against women! The criticisers simply don't like hearing what the research bears out.
I met John Malloy and bought his first books back in the late 1970's, and his advice REALLY helped me back then when I was a stock broker. I was delighted to see he had a new book out for women. I was not disappointed. He discusses all the ways women's professional dress has changed, and has good research to back up his conclusions, which he also shares with the reader. I have now changed professions--I am a teacher living overseas. I still found his advice very valuable, especially his new advice about "Casual Fridays," or any other business where dress is normally casual. Although I didn't know it before I read the book, this is the area which is now giving women the most trouble. He gives a lot of excellent advice--too much to summarize here. He covers many particular professions in detail.
One further note for buyers in England--in his first book, many years ago, when discussing color combinations, he explained that certain color combinations will work in one part of the United States (such as green suits for men in Minnesota are OK, but in other parts of the country men wearing that color would not be trusted), but not in others. This book is based on research done in the United States, and he mentions that certain European shades don't work well in America (he is specific about the ones that do not). Unfortunately, for British readers, while most of what he says will undoubtedly work there for you, read it carefully, in that there are bound to be some cultural differences causing different outfits to work somewhat differently (such as shades that may work well in America, but not in Britain).