I bought this one from one of the Reformed book stores as background for Wise Counsel.  The two books can be read profitably side-by-side. There are many biographies of Newton and this one may emphasize more than most the nature of the 18th century British slave trade, Newton's participation in it, and the public's attitude toward it. Did he continue his part in this terrible business after his conversion? Did he stop it because of conscience? Did he regret his part in the business? In his old age, with Wilberforce and others, he was a strong advocate for its abolition.