On a winter's night in 1974, a crime took place that would obsess the nation.

It was an extraordinary news story.

The story of an aristocrat, Lord Lucan, who's said to have killed the family Nanny,

mistaking her for his wife, then somehow just disappeared.

One of the great mysteries in English criminal history. We're still looking for

Lucan. It's honestly one of the most powerful stories of my lifetime. I'm Alex Fontunzelman. This is

the Lucan Obsession. Listen on BBC Sounds. BBC Sounds, music, radio, podcasts. Hello, I can't think of anything more apt to set the imagination stirring, drafting,

creating than the idea, the fact that anyone you walk past on the pavement may be a sadist,

a compulsive thief, or even a murderer.

Words from a 1989 letter by Patricia Highsmith,

whose novels, particularly those concerning her recurring anti-hero, Tom Ripley, plumbed the depths

of the psychopathic mind. But what made Highsmith so capable of creating a multitude of

ingenious and menacing scenarios?

And why did this hugely successful novelist always feel like an outsider?

Biographers have studied her life, but now we can enjoy the more intimate access

provided by the publication of an enormous volume of her diaries and notebooks, which were

discovered shortly after her death in 1995.

To help me explore them, I'm joined by their editor, Anna von Planter, down the line from Zurich,

and the novelist and trainee psychotherapist, Stella Duffy, here with me in the studio.

Welcome both of you to Open Book.

Thank you.

Anna, your relationship to Highsmith isn't just academic, but also a professional and personal one.

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