This book was written in the 40s or early 50s. Ruth (or is it Ann?) and her younger sister Laurie and brother-in-law Tommy and a couple of other people are all living in the same big house (don't remember why) and Ruth realizes that someone is trying to kill her. Someone waxes the bottom of her high-heels with paste floor wax (so that she may fall down the stairs.) Someone locks the door of the grandfather clock that she winds daily (so that tugging on it may pull it over.) Laurie is pretty and fluffy, Tommy drinks a little too much. They're always playing cards.

If there is a bit of a zany or slapstick element, it may be one of the books written by Constance and Gwenyth Little.

No, all deadly serious, I think, but thanks for trying. I remembered that it's gin rummy that Laurie and Tommy play. So frustrating. This was one of my all time favorite books and of course I loaned it to someone and didn't get it back. It was a library book that my mom bought off a remainder table at a local department store, so it must have had some circulation.

Hmmm. It sounds like one I remember where the older sister, a very wealthy woman, has a heart condition and the younger sister and the man are trying to scare her into an early grave so they can inherit, but the man was the older sister's fiance, not the younger one's husband. It took place in San Francisco. Is this ringing any bells?

Money is the motive, and Ruth is the one who has the money or is controlling it, but I don't remember anything about a heart condition. I suppose it's possible that Tommy is her fiance instead of Laurie's husband, but it seems unlikely because Ruth is the responsible one and Tommy is something of a loveable ne'er-do-well. There must be another man in the mix somewhere. Also don't remember any San Francisco connection. You don't remember the name of the one you're thinking of, do you? I keep hoping this discussion will jog my memory, but so far no luck.