10 Things I Loved About The Agency Series by Y. S. Lee

Mary Quinn was only twelve years old when she was sentenced to death. Turning to thievery after the death of her parents, she managed to scrape out an existence on the streets of Victorian London, but after being rescued from the gallows and given a home in a school for girls, her life took a turn for the better. Now she's seventeen and learns that the school is more than it seems. She's given the chance to train as a spy in an agency of women who take advantage of the way girls and women are overlooked and taken for granted. As she faces a variety of mysteries, villains, challenges, and a chance at romance, Mary has to deal not only with the dangers of her work but also with the weight of her past and her heritage. Can she come to grips with who she is or will she lose everything she's worked to gain?

I received the second book of the series - The Body at the Tower - at BookExpo America several years ago. I couldn't read them out of order, of course, so I tracked down the first book. After reading the first two I had to read the third and fourth as well!
This review contains some mild spoilers for the series, since I'm looking at it as a whole, but I'll try to keep it as spoiler free as possible.
So here we go - 10 things I loved about Y. S. Lee's Agency series

1. Mary - I liked how resourceful and determined she was. Yet she really struggled with how to survive in a world where she was considered a second class citizen on several different levels. She has to learn how to be comfortable with who she is and with the choices she's made.
2. James - The banter between Mary and James was probably my favorite part of the books (and there was far too little of it in the fourth one!). I liked how he developed as a character. It was nice that he had his own family and other things to deal with, even though the series was focused on Mary.
3. Their relationship - minor spoilers - I really appreciated that Mary and James went their separate ways at the end of the first book. And I liked the way Lee brought them believably back together again. The development of their relationship happened at a good pace, I thought.
4. Spies! - I really enjoyed the way Lee played with the cultural mores in Victorian England. And even if there wasn't a female agency like this, I know there had to be women who would have excelled at that kind of subterfuge. Because women were often overlooked and would have been able to gain information as servants, governesses, etc.
5. The setting - Lee did a good job of evoking Victorian England through the little details - the clothes, the food, the descriptions of setting woven in through the mystery.
6. The ethnic issues - minor spoiler - Mary is half Chinese and I really appreciated the way Lee dug into the prejudices and challenges of Asian people in London at the time. It's not something I've ever really heard about before and she wove it into the narrative in such an interesting way.
7. The mysteries - I liked the way that each book had its own distinct mystery which was wrapped up by the book's end. There were larger threads that carried through the series and call backs to earlier events and people, but it was kind of nice having a sense of closure at the end of each book. Also, each mystery was different and had its own challenges and approaches to solving it.
8. The layers - There was the larger mystery, but there were also plenty of other things going on to flesh out the stories and the characters - conflict in the Agency, Mary's conflicted feelings for James, trying to figure out who she is apart from the Agency, dealing with her past, James dealing with his brother and familial obligations - it just made for a much more interesting larger story. And I thought Lee did a good job of balancing all those different layers.
9. A complete story - I'm kind of glad I didn't get around to reading this until now, because I was able to read all four books one right after the other and get the whole story. I thought Lee did a good job of keeping you reading and wanting to know what happens in the next book and then by wrapping it up well in the fourth book. There's a real sense of closure but also a recognition that there are still a lot of possibilities left for Mary (and James).
10. The ending - Spoilers! - I liked the way the fourth book tied back to the first book and wrapped up the loose ends from the first mystery. I especially liked the way Lee wrapped up Mary's family story as well. It just completed the larger story pieces really nicely.