William Wilberforce (24 August 1759 – 29 July 1833) was an English politician, philanthropist, and a leader of the movement to stop the slave trade. A native of Kingston upon Hull, Yorkshire, he began his political career in 1780, eventually becoming an independent Member of Parliament (MP) for Yorkshire (1784–1812). In 1785, he became an Evangelical Christian, which resulted in major changes to his lifestyle and a lifelong concern for reform.

Collection consists largely of correspondence to and from William Wilberforce, with subjects ranging across abolitionist politics in Great Britain, business correspondence about the West India Committee, and personal family news and health. Correspondents include British politician William Pitt (the younger); Thomas Harrison, a close friend and a member of the Duke of Gloucester's West India Committee; Hannah More, an English writer and philanthropist; his close friend John Scandrett Harford, Jr. of Blaise Castle (near Bristol, England); George Montagu, Fourth Duke of Manchester; Lord Brougham; Spencer Perceval; Thomas Chalmers; George Canning; and John Bowdler (d. 1815).

Letters from this collection, particularly in the 1810s, often reference slavery and Wilberforce's work with abolitionists. In one letter of Aug. 10, 1814, Wilberforce wrote Harrison that he had been able to persuade Thomas Clarkson not to attend the Congress of Vienna. Articles appeared in The Edinburgh Review during 1814 which questioned William Pitt's motives in supporting the abolitionists. Wilberforce (Oct. 22, 1814) wrote Harrison concerning his relations with the younger Pitt (d. 1806), and stated that his belief was that Pitt had been a "sincere friend" of the abolition movement. Other letters for 1814 mention such things as the West India Committee and its membership, including the Duke of Gloucester, Lord Grey, Marquis Lansdowne, and Lord Grenville (Mar. 20 and Apr. 20), and the planned composition and distribution of pamphlets describing the evils of the slave trade and advocating its abolition (Apr. 26 and Oct. 3). The letter of Apr. 26 suggests the establishment of a special board, sanctioned by the King, to see to the composition of such works. Other letters from this period are between Wilberforce and Harford. One letter of Oct. 12, 1814, speaks of French publications which favor abolition and mentions Chateaubriand, Humboldt, Sismondi, and Madame de Staël. It also tells of the Duke of Wellington, the King of France (Louis XVIII), Prince Talleyrand, and the English Prince Regent (later George IV) as being favorable to abolition. A letter of Nov. 23, 1814, continues to speak of abolition in the light of world events, and Wellington and Tallevrand's correspondence with him. One fragment of a strong letter, dated 1815, gives a graphic account of two slave ships. This letter also asks Harford to try to interest the Roman Catholic Church in banning the slave trade. Wilberforce also mentions trying to interest Sir Thomas Acland and Lord Castlereagh in making an attempt to interest the Pope in the abolition of the slave trade. In 1817, Wilberforce was bothered by the hostile pamphlets of one of his opponents, the anti-abolitionist Joseph Marryat. Wilberforce wrote to Harrison concerning this matter on Aug. 4, 1817, and discussed the urgency of having one of James Stephen's speeches in answer to Marryat printed and distributed as soon as possible. Wilberforce recognized the need for much printed material to educate the peoples of all countries, and especially the "unprincipled Frenchmen" (letter of Aug. 5, 1821), in support of abolition of slavery. A July 9, 1816, letter speaks of Zachary Macaulay; and a May 7, 1817, letter tells of a Macaulay letter falling into the hands of Joseph Marryat. Wilberforce also speaks bitterly of Marryat's attack on himself.