This is an incredibly comprehensive overview over the Marxist conception of class. Szymanski goes in the historical development of class inequality and the class structure of advanced capitalism, he treats the classes extensively focusing his research on the United States, he also goes into its relationship with Race and with Patriarchy and finishes with his critiques of various different models of conceptualizing class society.
Sometimes he gets lost in the nitty-gritty of numbers and statistics which distract from the points he wants to make. He also tends to make leaps on the basis of mathematical assumptions that were sometimes either not necessary or lessening his arguments.
But all in all, I feel like this book as well as his other works are so well written and researched and cover a number of fundamental topics which makes them essential reading in my opinion.