This is the second book of the Mortal Instuments series. I was hooked with City of Bones so I couldn't wait to read this one. I love the world she created. She is a great storyteller and literally my favorite writer of 2010. I had a chance to interview her for my website. You can check out that interview here: http://www.yafantasyguide.com/author-interviews/cassandra-clare.htm