I recommend Tony Judt's
The Memory Chalet, a book of essays written as he became immobilized in body by Lou Gehrig's disease. It's getting 5 stars on Amazon. The writing is graceful. Judt, now dead, was a Londoner, of Jewish heritage, a historian who taught on both sides of the Atlantic but ended up in New York City.
I want to quote from the essay "Bedder".
"I grew up without servants. This is hardly surprising: in the first place, we were a small, lower-middle-class family who lived in small, lower-middle-class housing. Before the war [WWII], such families could typically afford a maid and perhaps a cook as well. The real middle class, of course, did much better: upstairs and downstairs staff were well within the reach of a professional man and his family." [His parents could afford a day-nanny for him. At Cambridge he had "bedders": women who looked after undergraduate rooms. Oxford has "scouts".]
Judt's class-consciousness is British, as are his gradations. I think he means his family was middle-class because they weren't "working class/lower class"; they had white-collar jobs, not manual labor. The "lower" part probably implies no college education, not a professional lawyer, teacher, manager. I think it's generally true a higher proportion of Brits had servants (say from 1850-1950) than Americans. Americans had "help", neighbor girls who might come in after childbirth or during sickness. But anyone who could afford regular employees probably was considered upper-middle-class.
Having noted this bit in Judt, I was struck when I saw on a newscast a talking head describing a growing "underclass" resulting from people losing their jobs in the Great Recession and being unable to find new employment. To me "underclass" is a bit pejorative, although perhaps not as much as "lower class" would seem.