Ichiro Kishimi and Fumitake Koga are the co-authors of The Courage to Be Disliked and its follow-up, The Courage to Be Happy, which extend their interpretation of Adlerian psychology. Koga, born in 1973, is an award-winning professional writer who encountered Adlerian psychology in his late twenties and was deeply affected by its conventional wisdom–defying ideas, having also released numerous bestselling works of business-related and general non-fiction.