Political thinker and philosopher; wrote many works devoted to expanding and humanising utilitarian philosophy; deeply concerned with social welfare; the most influential thinker of his time, personifying the best of mid-Victorian liberal opinion. His autobiography, a pioneering essay in psychological self-analysis, is one of the most significant of the Victorian era. Called On Liberty, it concentrates on Mill's personal and intellectual development, including the mental crisis he suffered in his youth, which lead him to reject many of the educational theories of his father, James Mill. A replica of the portrait commissioned by Sir Charles Dilke. Watts found Mill, who died shortly after he sat for the original, to be 'sensitive to all that was beautiful in form and poetic in thought'.