Spencer was a typographic designer, author, educator, researcher and painter. This versatile man opened his own London studio in 1948. He was a lecturer at the Central School of Arts and Crafts in London (1949–67), taught at the Royal College of Arts, where he became a professor of graphic arts (1978–85) and also a senior research fellow. The Post Office made him a consultant to their Stamp Design Committee (1968). He was the editor of Typographica magazine (1949–67) and Penrose Annual (1964–73). Herbert introduced modern European typography developments to the UK. Lund Humphries appointed him director of their publishing division in 1970. He designed for British Rail, the Imperial War Museum, WHSmith, the Tate Gallery, the Royal Institute of British Architects and Leeds University. Herbert wrote several important books, including his famous Pioneers of Modern Typography, The Visible Word and The Liberated Page. He was master of the faculty of Royal Designers for Industry (1979–81).