Southward became recognized as the leading authority on the history and processes of printing. His Dictionary of Typography and its Accessory Arts, after being issued as monthly supplements to the Printers' Register, was published as a book in 1872
Southward also published Authorship and Publication, a technical guide for authors, in 1881, and Artistic Printing: a Supplement to Practical Printing
Southward was active in philanthropic work and in 1888 founded, and for a short time edited, a monthly paper called Charity. During his later years he lived at Streatham, and died at St Thomas's Hospital, London, after an operation, on 9 July 1902. He was buried in Norwood cemetery.