How Many Artemis Fowl Books Have Been Published?

To date, there are six Artemis Fowl books. These are:

Artemis Fowl (2001)
Artemis Fowl: The Arctic Incident (2002)
Artemis Fowl: The Eternity Code (2003)
Artemis Fowl: The Opal Deception (2005)
Artemis Fowl: The Lost Colony (2006)
Artemis Fowl: The Time Paradox (2008)

Artemis Fowl is written by Irish author Eoin Colfer. Artemis Fowl is the main character, and is a criminal mastermind. The books are written in a half-serious language which alternates with dark moments, and is a style that is favoured by childrens' authors such as J. K. Rowling and Roald Dahl. Other books that Eoin Colfer has written include 'The Wish List', The Supernaturalist and 'Half Moon Investigations'. His first book, 'Benny and Omar' was published in 1998, and was based on his experiences on working in Tunisia.
In 2004, a companion book to the Artemis Fowl series was released, and contains two short stories, extra information, activities, and interviews with the characters and the author.

There are 6 Artemis Fowl books as of now.  They are:
Artemis Fowl (2001)
Artemis Fowl: The Arctic Incident (2002)
Artemis Fowl: The Eternity Code (2003)
Artemis Fowl: The Opal Deception (2005)
Artemis Fowl: The Lost Colony (2006)
Artemis Fowl: The Time Paradox (2008)
             All these books are great!!