The Shadowhunter Chronicles is a franchise comprising of nine young-adult fantasy novels written by American author Cassandra Clare.
The first set of novels, (originally a trilogy) The Mortal Instruments, was originally released between March 2007 and March 2009 in the United States, with international releases of each novel following shortly after the American debuts. The first book of the second collection, The Infernal Devices, debuted in autumn 2010. The third series, The Dark Artifices, is set to be released in 2015.
Each story follows the supernatural conflict between the Shadowhunters, a group of powerful human/angel hybrids, and the Downworlders, a society of mythological beings. Both tales chronicle young heroines who enter the conflict for personal reasons. Along the way, each becomes aware of her own powers while forging various new relationships, and making several discoveries about the journey, heritage, and family.
The Mortal InstrumentsEdit
The series is also being adapted into films, starting with the first, The Mortal Instruments: City of Bones, the first of possibly a trilogy, or more. The sequels will depend on the success of the first film.
The Infernal DevicesEdit
The Infernal Devices is set during Victorian England. It follows the journey of Tessa Gray and her companions within London's Shadow World. It is a trilogy made up of Clockwork Angel, Clockwork Prince and Clockwork Princess.
Also, The Infernal Devices has been optioned by for film by the same studios making the City of Bones movie. The screenplay is currently in the works. 
The Dark ArtificesEdit
The Dark Artifices will be set in modern-day Los Angeles, a mere five years after end of The Mortal Instruments series. It will follow Emma Carstairs. The current working titles of the books in the series are Lady Midnight, Prince of Shadows, and The Queen of Air and Darkness.
Cassie has revealed that she is currently planning the fourth series which goes by the initials TLH and takes place in the early 1900s, featuring the children of the characters from The Infernal Devices. 
She is also working on a trilogy that she has dubbed as the "secret project" which will take place three years after The Dark Artifices.