Sarah Cockburn was the daughter of Claud Cockburn, the left wing journalist, and his second wife Jean Ross, who was partly the model for Christopher Isherwood's Sally Bowles of Cabaret fame. She graduated in Classics from Aberdeen University and read law at St. Anne's College, Oxford. On coming down from Oxford she lectured on Law at the University College of Wales, Aberystwyth. Having been called to the Bar, she practised as a barrister for several years in Lincoln’s Inn and later specialised in international tax planning at Lloyds Bank. It was at this time that she started to write. Caudwell's three half-brothers Alexander Cockburn, Andrew Cockburn and Patrick Cockburn are also journalists. She was the half-sister-in-law of Leslie Cockburn and of Michael Flanders. Journalists Laura Flanders and Stephanie Flanders, and actress Olivia Wilde are her half-nieces.

She was one of the first two female students to join the Oxford Union, having, legend has it, dressed up in men's clothes to protest against its male-only membership policy. She was thus one of the first female students to speak in the Oxford Union's Debating Chamber.

She was a lifelong pipe-smoker, and inveterate crossword-puzzle solver, reaching the final of The Times Crossword Competition more than once and for many years lived in Barnes, London with her mother and aunt.

She died of cancer in January 2000.

This series of four books, described as "legal whodunits", were written over a period of twenty years. Their primary setting is the top floor of 62 New Square at Lincoln's Inn, where four young barristers have their chambers: Michael Cantrip, Desmond Ragwort, Selena Jardine and Timothy Shepherd. While the last named only appears sporadically, taxes barrister Julia Larwood, who works in the adjacent premises, is a regular visitor and is in effect the fourth member of the group. These characters are in some ways thinly drawn, never communicating in anything other than in an ironic tone, so that even when they are in deadly danger the atmosphere remains uniformly light-hearted. Even though the characters are sexually active, their cheerful friendship is sometimes reminiscent of the chummy gangs encountered in juvenile fiction.

Acting as a kind of parent to the group is the first-person narrator, Professor Hilary Tamar. Professor Tamar, a former tutor of Timothy Shepherd, also acts as the main detective, although other characters make contributions to the eventual solutions. Professor Tamar is frequently physically removed from the action and is kept informed by a series of improbably long letters and telexes. This distancing is amplified by Caudwell’s strategy of not specifying Tamar's sex and never specifying the reason for the strong bond which the character enjoys with the young advocates, notwithstanding the lack of any point of contact in terms of age, temperament, occupation or enthusiasms.

The books have a self-consciously literary style, including many references to the classics and other subjects of higher learning. One running joke is the narrator's absurd elitism, with lower orders such as Solicitors, Accountants, Tax Inspectors and Cambridge graduates being frequent targets of barbed comments; one character is disparaged as it is suspected he had to work in order to earn a first-class degree.

The plots are intricate, carefully realised, and strongly tied to the locations chosen, these being Venice, Corfu, Sark and an English village. The author’s expertise in tax law is frequently brought into play, inheritance law being relevant to financial motives for murder.

Caudwell collaborated on crime short stories with Michael Z. Lewin and with Lawrence Block (and others) for The Perfect Murder.

She also wrote a play, The Madman’s Advocate, which was given a rehearsed reading in Nottingham in 1995: a study of Daniel M'Naghten's attempt in 1843 to assassinate Sir Robert Peel and the resulting establishment of the M'Naghten Rule as a legal standard for defining the sanity of a defendant in law.

Hilary Tamar Stories

• Thus Was Adonis Murdered (1981)
• The Shortest Way to Hades (1985)
• The Sirens Sang of Murder (1989)
• The Sibyl in Her Grave (2000)

Other Novel

• The Perfect Murder: Five Great Mystery Writers Create the Perfect Crime (1991) (with Lawrence Block, Tony Hillerman and Jack Hitt)

Contributions to anthologies

• 2nd Culprit: An Annual of Crime Stories (1994)
• 3rd Culprit (1994)
• Malice Domestic 6 (1997)
• The Oxford Book of Detective Stories (2000)
• Women Before the Bench (2001)
• The Mammoth Book of Comic Crime (2002)