This is an interesting read from an earlier era. Basically, a woman named Amy Doll keeps boarders upstairs, and when she raises the rent, they resort to prostitution. The boarders are four middle-aged to post-menopausal women - one is almost wholesome, one is exotically foreign, and two are active alcoholics.
The novel explores many life situations, romance, poverty, domestic work, etc. A policeman comes to spy on the old tarts (or so Amy guesses), but ends up being a love-interest and an anchor which enables Amy Doll to demand an end to the unsavory activities upstairs.
The author might have made a stronger statement about the working wage, women in poverty, etc., but instead the writing is very plain and lacking in condemnation. The reader is left to draw their own conclusions. The situations are realistic, and this might be called "realism," although the sexual activity is mainly alluded to and not detailed.
It's a readable book, a product of its era. The contemporary reader might be surprised that such a topic could be dealt with in such a _clean_ manner.