<Table> The Mortal Instruments <Tr> <Td_colspan="2"> </Td> </Tr> <Tr> <Td_colspan="2"> <Ul> <Li> City of Bones </Li> <Li> City of Ashes </Li> <Li> City of Glass </Li> <Li> City of Fallen Angels </Li> <Li> City of Lost Souls </Li> <Li> City of Heavenly Fire </Li> </Ul> </Td> </Tr> <Tr> <Th> Author </Th> <Td> Cassandra Clare </Td> </Tr> <Tr> <Th> Cover artist </Th> <Td> Cliff Nielsen </Td> </Tr> <Tr> <Th> Country </Th> <Td> United States </Td> </Tr> <Tr> <Th> Language </Th> <Td> English </Td> </Tr> <Tr> <Th> Genre </Th> <Td> Romance, Young adult, Urban fantasy </Td> </Tr> <Tr> <Th> Publisher </Th> <Td> <Ul> <Li> Margaret K. McElderry (US) </Li> <Li> Walker Books (UK, Australia, New Zealand) </Li> <Li> Destino (Spain) </Li> <Li> Arena Verlag (Germany) </Li> <Li> Universal Poche (France) </Li> </Ul> </Td> </Tr> <Tr> <Th> Published </Th> <Td> March 27, 2007--May 27, 2014 </Td> </Tr> <Tr> <Th> Media type </Th> <Td> Print (hardcover and paperback) Audiobook </Td> </Tr> <Tr> <Th> No. of books </Th> <Td> 6 </Td> </Tr> <Tr> <Th> Preceded by </Th> <Td> The Last Hours </Td> </Tr> <Tr> <Th> Followed by </Th> <Td> The Dark Artifices </Td> </Tr> </Table> <Tr> <Td_colspan="2"> <Ul> <Li> City of Bones </Li> <Li> City of Ashes </Li> <Li> City of Glass </Li> <Li> City of Fallen Angels </Li> <Li> City of Lost Souls </Li> <Li> City of Heavenly Fire </Li> </Ul> </Td> </Tr>

How many the mortal instruments books are there