Stuart was educated at Framlingham College in Suffolk, leaving in 1941,[1] after which he served in RAF Fighter Command during World War II, achieving the rank of Flying Officer.

[1] Rossiter was employed as Assistant Librarian at Westminster City and Kent County Libraries and in 1954 joined the staff of the Blue Guides where he rose to become editor (1963–1973).

[2] His Blue Guides book on Greece was highly praised and as a result he was elected a Fellow of the Royal Geographical Society.

[4] As a student of postal history, Rossiter realised that a knowledge of geographical and political changes was essential to a proper understanding of philately.

The arduous task of locating such relevant information is what led Rossiter and John Flower, working through the renowned Blue Guides, to propose a Stamp Atlas, which was finally completed after his death in 1982.