As king, George III needed to maintain an awareness of the constitutional situation of the country. To this end his collection includes contemporary works on the state of public finances, land, civil and nautical law and Parliamentary debates. In addition, there are several contemporary and historic texts on legislation in the British Isles and in Europe.

Many Anglican service books, sermons and theological tracts are listed in George III's Windsor library catalogue, reflecting his role as Head of the Church of England. It is apparent that the king was a deeply pious man, not only owning religious texts, but presenting them to his children and to religious establishments. He was a great collector of sermons by prominent theologians of the day, many of which are listed in the Windsor library catalogue in the king’s own hand.