Most of Bach's books have been semi-autobiographical, using actual or fictionalized events from his life to illustrate his philosophy. Bach's books espouse his philosophy that our apparent physical limits and mortality are merely appearance. Bach is noted for his love of aviation and for his books related to flying in a metaphorical context. Bach has pursued flying as a hobby since the age of 17. In late August 2012, Bach was badly injured when on approach to landing at Friday Harbor, Washington, his aircraft clipped some power lines and crashed upside down in a field.