Publishing Deal - Cassandra Clare

From Publishers Weekly:

Simon & Schuster has signed books five and six in Cassandra Clare's bestselling YA series, The Mortal Instruments. S&S says there are more than three million copies of the series' three published titles in print. Clare launched The Mortal Instruments in 2007, with City of Bones, about a teenage demon slayer; City of Ashes and City of Glass followed. Book four, City of Fallen Angels, is scheduled for April 2011.

The two new books under contract--City of Lost Souls and City of Heavenly Fire--are scheduled, respectively, for May 2012 and September 2013.