Question: What is the name of the first book in the series based on a stealth video game series developed by the Danish company IO Interactive?

Context paragraphs:
Syphon Filter: Syphon Filter is a third-person shooter stealth video game series developed by SCE Bend Studio (formerly Eidetic) and published by Sony Computer Entertainment (previously 989 Studios), that has appeared on the PlayStation, PlayStation 2 and PlayStation Portable game systems.  In the series, "Syphon Filter" is the name given to the mysterious biological weapon.

Hitman: Enemy Within: Hitman: Enemy Within is the first novel in the "Hitman" series.  It was written by William C. Dietz and released on August 28, 2007, from Del Rey Books.  The novel's plot is set between "Hitman 2: Silent Assassin", "Hitman: Contracts" and "Hitman: Blood Money" and revolves around a rival murder-for-hire organization, known as "Puissance Treize" (French for "Power Thirteen"), attempting to destroy Agent 47's employer, the International Contract Agency (ICA).  The book's tagline is: "The clone assassin has been played long enough – now it’s more than a game."

Hitman: Codename 47: Hitman: Codename 47 is a stealth video game developed by IO Interactive and published by Eidos Interactive exclusively for Microsoft Windows.  It is the first installment in the "Hitman" video game series.

Hitman 2: Silent Assassin: Hitman 2: Silent Assassin is a stealth video game developed by IO Interactive and published by Eidos Interactive for Microsoft Windows, PlayStation 2, Xbox and GameCube.  It is the second installment in the "Hitman" video game series and the sequel to "".  The game was re-released for Windows through the Steam online distribution service and later a DRM-free version was available through GOG.com.  A commercial success, the game has sold more than 3.7 million copies as of 23 April 2009 and is the best selling "Hitman" game to date.

Hitman (2016 video game): Hitman is an episodic stealth video game developed by IO Interactive and published by Square Enix for Microsoft Windows, PlayStation 4, and Xbox One.  A port for Linux, developed and published by Feral Interactive, was released on 16 February 2017.  A version for macOS, also developed and published by Feral Interactive, was released on 20 June 2017.  It is the sixth entry in the "Hitman" series.  The game's prologue acts as a prequel to "", while the main game takes place seven years after the events of "".

Hitman: Contracts: Hitman: Contracts is a stealth video game developed by IO Interactive and published by Eidos Interactive for Microsoft Windows, PlayStation 2 and Xbox.  It is the third installment in the "Hitman" video game series.  As of April 2009, the game has sold around 2 million copies.

Hitman: Absolution: Hitman: Absolution is a stealth thriller video game developed by IO Interactive and published by Square Enix.  It is the fifth installment in the "Hitman" series, and runs on IO Interactive's proprietary Glacier 2 game engine.  Before release, the developers stated that "Absolution" would be easier to play and more accessible, while still retaining hardcore aspects of the franchise.  The game was released on 20 November 2012 (which is in the 47th week of the year in reference to the protagonist, Agent 47) for Microsoft Windows, PlayStation 3, and Xbox 360.  On 15 May 2014 "Hitman: Absolution — Elite Edition" was released for OS X by Feral Interactive; it contained all previously released downloadable content, including "Hitman: Sniper Challenge", a "making of" documentary, and a 72-page artbook.

Hitman (series): Hitman is a stealth video game series developed by the Danish company IO Interactive.  Previously published by Eidos Interactive and Square Enix.  IO Interactive remained a subsidiary of Square Enix until 2017, when Square Enix started seeking sellers for the studio.  IO Interactive completed a management buyout, regaining their independent status and retaining the rights for "Hitman", in June 2017.  The series is available on Microsoft Windows as well as several video game consoles, including the Xbox, PlayStation 2, GameCube, Xbox 360, PlayStation 3, Xbox One and PlayStation 4.  The franchise includes two novels, "" written by William C. Dietz, followed by "Hitman: Damnation".

IO Interactive: IO Interactive A/S (IOI) is an independent Danish video game developer based in Copenhagen, Denmark, best known for developing the "Hitman" series.  The company was founded under the name ASX Nr.  14.811 ApS on 1 November 1990, and became Mermaid Invest ApS on 24 May 1992.  On 16 September 1998, the Reto-Moto development group turned the company into IO Interactive ApS, and into IO Interactive A/S on 14 April 2000.  Originally a private studio, they were purchased in 2004 by their publisher, Eidos Interactive; Eidos was subsequently taken over by Square Enix Europe, a subsidiary of Square Enix, in 2009.  IO Interactive remained a subsidiary of Square Enix until 2017, when Square Enix started seeking buyers for the studio.  IO Interactive completed a management buyout, regaining their independent status and retaining the rights for "Hitman", in June 2017.

Hitman: Blood Money: Hitman: Blood Money is a stealth video game developed by IO Interactive and published by Eidos Interactive for Microsoft Windows, PlayStation 2, Xbox and Xbox 360.  It is the fourth installment in the "Hitman" video game series.

Supporting paragraphs: Hitman: Enemy Within Hitman (series)
Answer: Hitman: Enemy Within