Alethea Hayter was born and spent her early childhood in Cairo, Egypt, where her father Sir William Hayter, was a legal and financial adviser to the Egyptian government in the waning years of the British Protectorate; her mother Alethea Slessor was the daughter of a Hampshire clergyman. Her brother Sir William Goodenough Hayter went on to become British ambassador to the Soviet Union and her older sister Priscilla Napier became an acclaimed biographer. After her father died when she was 12 years old, the family returned to England in reduced circumstances. Alethea won a scholarship for her education at Downe House School, in Berkshire, and at Oxford University, from which she graduated with a BA in modern history. She joined the editorial staff of Country Life magazine, where she worked until 1938. During World War II, she served as a postal censor in London, Gibraltar, Bermuda, and Trinidad. In 1945, she joined the British Council, and in 1952 was posted to Greece as an Assistant Representative. In 1960, she went to Paris as Deputy Representative and assistant cultural attaché, and her apartment became a meeting place for writers and artists. Her first book, on the poetry of Elizabeth Barrett Browning, appeared in 1962. Over the next 10 years, she published several other memorable works of literary biography: A Sultry Month (1965), Opium and the Romantic Imagination (1968), Horatio's Version (1972) and A Voyage in Vain (1973). Her last British Council posting was as Representative to Belgium, and she retired in 1971. She was a member of the governing bodies of the Old Vic and Sadler's Wells theatres and of the management committee of the Society of Authors. In 2002, she published The Wreck of the Abergavenny, about the shipwreck of the East India ship in 1805 and the death of its captain, William Wordsworth's brother John, emphasizing its effect on the Wordsworthy family and their friends and connections.