A pretty good mystery, set in colorful 1940s New York City. It has Chandleresque prose, and I'm a sucker for that. It also has sort of a Nero Wolfe vibe. (I think. I've only read one of those, years back.) Specifically, it features a two-person team of detection, one being rich and more or less the brains of the operation; the other being young, scrappy, and smart-mouthed. And, oh yeah, they're both women.
In this case the Wolfe-like character is Lillian Pentecost, who has an established detective agency. The Archie Goodwin-like character is Willowjean Parker, the book's narrator, who (really) ran away from home to join the circus. She also takes on temp jobs, which causes her to meet Lillian, who's immediately impressed with Willowjean's powers of observation and skill at knife-throwing. The latter skill probably saves Lillian's life, so that's good too. They team up.
A few years later, they take on one of those classic mystery plots: A wealthy widow, whose war-profiteering husband apparently committed suicide previously, throws a party. A seance is performed by a mysterious (but also wealthy) lady medium, quickly followed by a grisly murder. In a locked room, no less.
The cops are on the job, but the surviving family members hire Lillian to assist. She and Willowjean start uncovering layer after layer of the nasty plot, experiencing plenty of peril along the way. And there's an actual did-not-see-that-coming plot twist at the very end, which (I bet) sets up followup novels in the series.
Did I mention that Willowjean (um) apparently swings from both sides of the plate? Something Rex Stout probably never thought of doing to Archie Goodwin.
I was slightly irked by a reviewer who says the book "plays fair with the reader". Well, not always. Another classic mystery trope: Willowjean's narration hides certain facts from us, only to reveal them later. That's not my cup of narrative tea, but I'll allow it.