Tim Cook answered
The Witcher series comprises the 2007 release The Witcher, its sequel The Witcher 2: Assassin of Kings (2011) and the forthcoming The Witcher 3: Wild Hunt, due for release in February 2015.
Did You Mean Who Published, Rather than Developed, the Series?
In North America, the publishers of the first two Witcher adventures were the legendary Atari, Inc. The third game is being developed by Warner Brothers Interactive Entertainment.
If you'd like a sneak preview of The Witcher 3: Wild Hunt, take a look at this demo unveiled at GamesCon 2014: