Strong introduction to the series. The Agency itself is a cool concept. The Agency is an all female detective agency which exploits the subordinate place of women in 19th century Victorian society to place spies in intelligence gathering roles as maids, governesses, etc. Good mystery that develops well(Mary goes undercover as a companion to a rich young woman to investigate her father for trade/financial improprieties), interesting central character. I really liked Mary and found her back story interesting. They laid the ground work nicely for subsequent books with the mystery of Mary's father and her conflicted feelings over her heritage and her past. Very quick read.