Stefan Klein (born October 5, 1965) is a physicist, author, essayist and visiting professor at Berlin University of the Arts.

He left his academic career to become science editor at Der Spiegel, a newsmagazine, in 1996, and quickly made a name for himself through a series of ten highly regarded cover stories.

[1] His 2002 book The Science of Happiness is a synthesis of findings from neuroscience, social psychology and philosophy on how positive emotions can arise in the human brain.

However, Klein believes subjective well-being can be raised by training the awareness for positive emotions when they are generated in the brain.

[8] Alison Abbott from Nature Magazine called The Science of Happiness "an extremely well-written, easy-to-read and expertly researched book on a theme which has long been begging for pop-science treatment".