John Cassell (23 January 1817 – 2 April 1865) was an English publisher, printer, writer and editor, who founded the firm Cassell & Co, famous for its educational books and periodicals, and which pioneered the serial publication of novels. He was also a well-known tea and coffee merchant and a general business entrepreneur. A fervent Christian, he campaigned throughout his life for the temperance movement in Britain, for the reduction of taxes on publishing, and was a social reformer who recognised the importance of education in improving the life of the working class, and whose many publications, both magazines and books, brought learning and culture to the masses.