Weird interesting book. Like most business/self-help books, there is a lot of fluff. But at the heart of it is someone who is extremely perceptive about how to navigate class mobilization and wants to share this insight with other ambitious "outsiders." The book is written in the mid-90s, so the cultural references are certainly dated, but the overall description is sound. If anything, the class structure he describes is even more rigid now than the boom-time of the 1990s. I have never seen anyone take sociology and turn it into an instruction book. It highlights what is often missing in most self-help books - the excessive focus on "self" when so much of "success" involves how you relate to other people.
I would say the key take aways from this book are (1) there is a class structure American society (less controversial to say now) with unique cultural markers at each level. Coleman identifies 7 levels relevant to work roles. E.g. level 1 are those unable to work, level 3 is minimum wage, level 5 are middle managers, small business owners, professionals like doctors, lawyers, level 6 are CEOs, celebrities, "new money" and level 7 is "old money" and world leaders. (2) its not money or accomplishment that determines which level you are in but belonging - do you fit in culturally with that level (3) to move up a level you need to be sponsored by someone in that level (4) Once a level has welcomed you in as one of their own *the means by which to support the lifestyle of that level are provided to you.*
This is an interesting contrast to something like The Millionaire Next Door, which focuses on maintaining your lifestyle and cultural class as a means to accruing significant wealth and material security.
He is also upfront about the price it takes to climb into another level and that it is perfectly reasonable to find that price unacceptable or the level which you are at to be great. When he describes the social life of level 7 (state dinners) and level 6 (formal cocktail parties), he notes that these events are not leisurely at all but play a vital role in networking and business deals. In contrast, socializing in level 3 or 4 is focused on family, relaxing at barbecues and beers on a porch. Depending on your preference i suppose, level 3 and 4 parties sound way better.
Setting aside that it is possible to have other structures of society - more equitable, less hierarchical - Coleman provides an insightful map of how things are right now that are useful for class strivers and those who wish to break the whole thing.