This is the first book in the Phryne Fisher series, and it's golden. The introduction is priceless, as the young lady puts Sherlock Holmes to shame in the instantaneous and almost offhand solving of the theft of a necklace.
The whole book is a bit like that, brisk and breezy and offhand. Phryne Fisher is a creature unto herself, unconcerned by anyone's opinion and a bit puzzled, if anything, if it comes to her attention that someone disapproves; she's the sort who, if disapproval is detected, will proceed to emphasize that trait or behavior being frowned upon. She was born independent, and has no more real need for anyone than a frog needs a harmonica.
Yet I liked her. Once I got used to her casual attitude toward sex and drugs (rock 'n' roll not having been invented yet), which were so not what I was expecting but which actually slotted into the time period well enough (there are reasons they were called the Roaring Twenties), I liked her. Not as much as I love Kerry Greenwood's other main heroine, Corinna, but I don't regret buying every single one of the books in the series. (Fortunately.)