This was Heyer’s second book, and her first big success. The first, BLACK MOTH, was apparently written to amuse her sick brother, and was something of a melodrama. In this one, she hit on the formula that was to make her a fabulously wealthy woman and invented a genre at the same time. It came out during the General Strike, and thus had no publicity. The fact that it was still a best seller confirmed Heyer in the idea that she did not need to do interviews.
In this one, a Duke takes on a new page, and over time we learn she is in fact a girl, and through a series of unlikely events in fact the legitimate child of his greatest enemy. They fall in love and etc. It’s a reasonable book, and you can see she still thought of it as a book, rather than as a formula. Next up, the sequel, DEVIL’S CUB.