I have really started to develop a soft spot for Patricia Wentworth, which is awesome because she wrote so many books that I'll be busy with her backlist for years. Decades, maybe.
Eternity Ring is nominally a Miss Silver mystery, although she barely appears in the book at all. The main investigator is Frank Abbot, who is a likeable Scotland Yard Inspector. As has been in the case in the two prior Miss Silver mysteries that I've read, this one also had a strong romantic subplot, with a young married couple, Cicely and Frank Hathaway who have separated before the murders begin. When the shadow of suspicion begins to fall on Frank, their future is seriously in jeopardy.
I figured out the murderer pretty early in the book by process primarily of elimination. It's a good mystery, though, and has some tense moments of real danger near the end of the book. I enjoy Wentworth's romantic subplots more than Georgette Heyer's romantic subplots (in her mysteries), and wonder that she never wrote straight up romance. I think she would've been pretty good at it, actually.
I still think that I liked Latter End a bit better than this one, and the first one I read, Grey Mask, remains my least favorite of her books. I have a few more on my kindle, and my library has about 25 available, so it'll be a while before I exhaust my ready supply.