 Lady Simon again demonstrated her interest in the rights of African Americans in 1928, when she attended the dedication of the Wilberforce Monument alongside the NAACP president Walter Francis White.Throughout the 1920s, Lady Simon researched chattel slavery throughout the world, but especially in the British Empire and British protectorates, and deemed that there were more than 6 million "living in bondage" worldwide.The highly successful book, titled "Slavery", was published in 1929 and was dedicated to "Amanda of Tennessee".