Sellar was educated at Fettes College where he was Head Boy. After serving briefly in World War I he took a degree at Oriel College, Oxford (which, as recorded in 1066 and All That, was awarded through an aegrotat) and worked as a schoolmaster at his old school. He later taught at Charterhouse School until his death.
Yeatman had won the Military Cross in World War I before going to Oriel where he met Sellar. He went into advertising and became advertising manager for Kodak Ltd. When asked to convert his BA from Oxford into an MA, Yeatman could not find the fee owing to debt, and hence he is recorded in 1066 and All That as "Failed MA, etc., Oxon".
Sellar was born at Golspie in Sutherland, the descendant of Patrick Sellar who had taken a leading role in the Highland clearances.
Sellar had begun to contribute to Punch in 1925 when three humorous short stories of his were published (he also contributed to other journals around this time).
Sellar's contribution is particularly noted in the comic exaggerations and name confusions; his knowledge of English literature also inspired the book's many literary allusions and pastiches.
Walter Carruthers Sellar (1898 - June 11, 1951) and Robert Julian Yeatman (1898 - July 13, 1968) were British humourists who wrote for Punch, and are best known for their book 1066 and All That (1930, ISBN 0413772705), a tongue-in-cheek guide to "all the history you can remember".
Sellar was educated at Fettes College where he was Head Boy.
Yeatman had won the Military Cross in World War I before going to Oriel where he met Sellar.