Lysander Spooner : Individualist Anarchist and Unitarian Christian Abolitionist : The greatest natural rights thinker of the 19th century was the American lawyer and maverick individualist Lysander Spooner. He responded to the tumultuous events of his era, including the Panic of 1837 and the Civil War, with pamphlets about natural rights, slavery, money, trial by jury and other timely subjects.