Max Martin

Karl Martin Sandberg, known professionally as Max Martin, (born 26 February 1971) is a Swedish music producer and songwriter. Raised in Sweden, he became a producer and songwriter in the mid 1990s after writing a string of hits for pop artists like the Backstreet Boys, Britney Spears, *NSYNC, Kelly Clarkson, Katy Perry, and Pink, Taylor Swift, among many others. 
Career.
Some of his earlier hits include I Want It That Way, Baby One More Time, "Larger Than Life", "Show Me the Meaning of Being Lonely", "Oops!...I Did It Again", "Everybody (Backstreet's Back)", "That's the Way It Is", and "It's My Life".
He also helped the Cheiron Studios create the Album "The Bridge", which has sold more than six million copies worldwide, including one million in the United States.