I was so pleased to see that this is actually the first book in the series. I had thought it was a stand alone novel.
Black has created an interesting universe where a small percentage of the population has the ability to work curses. These curse workers (known as "workers") will be good at one type of magic. Luck, death, transformation, dreams, memory, etc. As with most books, there is a price for doing magic and this time it's related to the kind of magic they do. So for example, a worker might be able to alter, remove, or block memory but each time he does he might lose one of his own memories.
Cursing someone is banned, so naturally the people with cursing ability mostly deal with crime families and the black market. Curses are passed by skin to skin contact usually through the hands and since no one knows who has the ability everyone wears gloves.
There's not much exploration of the cost of working curses, which I think is too bad. We certainly see the effects of people who have frequently used their ability, memory workers with Alzheimer's like mental states, emotion workers who are emotionally unbalanced but no one seems to think about whether the blowback is worth whatever curse they're working. I think the transformation worker gets off the lightest. It's incredibly painful but there doesn't seem to be any permanent effects. There's also no discussion of what happens to the dream worker. Nightmares? Inability to dream?
There are some interesting questions that relate to the modern day. There's a new test involving brain waves that allows doctors to objectively test for curse working ability. There's a campaign for mandatory testing, promising to keep the results confidential. Of course, no one believes they'll actually stay that way.
There are also some interesting moral and ethical questions about how far people are willing to go to get what they want. Does it matter if your spouse only loves you because s/he's cursed to feel that way?
The ending was heartbreaking but all the more perfect because of it.