After her mother's death, Rosalind Bleach inherited, with her sister, a prized rosewood bureau, which they both remembered as having been very private. In fact, it took years of painstaking research to unravel the literary secrets it contained.

Rosalind, who lives in Wolvercote, said: "Underneath the bureau was a slim Radamakers chocolate box labelled in my mother's hand: 'Letters of Henry James to Mrs Francis Ford'." The faded label on the lid of the box read: 'Given to Chloë by Mrs Ford's son, Morton Stephenson, in 1941'.

The sisters' first reaction was of puzzlement. There was no surname James' in their family, they thought. It took only a little more investigation to find that these letters, folded to quarter size to fit in the envelopes of the time, were written on paper headed Lamb House, Rye, Sussex - the novelist's home from 1898-1916, where he had exchanged letters with his neighbour and friend Mrs Francis Ford.

But who was Mrs Ford? She was obviously a good friend - one letter concludes: "It is unspeakably lovely the waistcoat & absolute perfection.... Ever most emotionally yours Henry James." And who were the various relatives and friends referred to in the text?

Gradually, Rosalind realised that a literary detective story was in her hands and it would be her mission to unravel it. This could not be done immediately, but eventually Rosalind reduced her working hours - she is a speech and language therapist - and set about creating the book. Initially, she turned to the Bodleian Library for help, not only to authenticate the famous signature, but with actually reading the letters, which was not an easy task. She also took a creative writing course at Oxford University's Continuing Education Department.

Henry James had the habit of the time, which was to finish letters with any last thoughts that didn't fit on the page by writing crossways on any spare bit of space left. It may seem messy now, but casual correspondence then was the equivalent of emails today - quick communication with no thought to layout or posterity. Rosalind received expert help from Clive Hurst, Head of Special Collections at the Bodleian, and was then put in touch with Philip Horne, Professor of English Literature at University College, London, the editor of Henry James; f=iA Life in Letters (1999). He took a great interest in the letters, gave advice and wrote a foreword to the book. Indeed, it was Philip Horne who suggested that George Ramsden was exactly the right man to publish such a book in its entirely appropriate turn-of-the-last-century livery, through his publishing house, Stone Trough Books.

Early in her research, Rosalind talked to her mother's sister, who could just remember meeting Mrs Ford; together they made a pilgrimage to Lamb House. Rosalind remembers feeling very moved by seeing the very rooms in which Henry James must have written many of the letters. When she came to the telephone room (the installation of the telephone is excitedly described in one of James' letters), it felt like touching the past. On impulse, she and her aunt set off to find Budds, the home of Mrs Ford.

They drove into Wittersham and inquired at a local antique shop. Yes, Budds still existed - go up the road and turn right. They did not know what reception they might receive. Another piece of serendipity took place. The house is now owned by Labour Peer Lord Alli and his partner, media tycoon Charlie Parsons. Despite being in the middle of a tea party, they warmly invited the sisters in, and could not have been more helpful and supportive of the project.

Rosalind has brought together James's side of the correspondence in a slim volume called Henry James's Waistcoat, beautifully produced by Stone Trough Books. So, who is going to buy this gem of a book? Aficionados of Henry James, naturally, and I suspect, discerning readers who stand outside the common circle and look for books that don't fit into rigid categories but simply exist in their own right. This literary gem would be a perfect gift for that academic uncle (or aunt) for whom you never know what to buy. Believe me, this time their faces will light up.

It is all set to become a rare book of the future, all the more so because it has a limited print run.

Henry James's Waistcoat is available from Blackwell's, The Book House in Summertown and Lamb House, Rye, or on order from any good bookshop, ISBN 978 0 9544542 1 6.