Conan Doyle, by Andrew Lycett<br/>Arthur Conan Doyle: A Life in Letters Ed. John Lellenberg, Daniel Stashower & Charles Foley

Conan Doyle would probably be relegated to the footnotes of literature if it had not been for Sherlock Holmes. The world's greatest detective gave Doyle fame, fortune and the sort of life he wanted, but it proved a Faustian pact. One of its consequences is that Holmes's shadow has obscured the complex reality of his creator.

Both these books go some way to rectifying the imbalance, though in very different ways. Both draw on the tranche of papers (particularly letters) recently acquired by the British Library, many not previously in the public domain. Andrew Lycett, whose books include biographies of Kipling and Dylan Thomas, provides a detailed and admirably even-handed account of Doyle and his career. Objectivity is a rare quality where his life is concerned, since his heirs have tended to choose biographers who could be trusted to agree with them.

The Life in Letters, on the other hand, is clearly a partial affair in both senses of the adjective. One editor, Charles Foley, is Doyle's great nephew; the others are American aficionados, members of the Baker Street Irregulars. Nevertheless, the book gives an unusually intimate glimpse of the private man behind the Holmes myth and the Conan Doyle bombast. The letters are supplemented by a commentary and extracts from Doyle's memoir, Memories and Adventures.

Born in 1859 of predominantly Irish descent, Doyle qualified as a doctor at Edinburgh, where he met Dr Joseph Bell, whom he later acknowledged as the principal inspiration for Holmes. After qualifying, he went into general practice, augmenting his income with increasingly ambitious short stories. Holmes and Watson first appeared in a short novel, A Study In Scarlet (1887). But not until the first of 56 short stories, "A Scandal in Bohemia", appeared in the July 1891 issue of The Strand Magazine did Holmes's extraordinary career hit its stride – in a case where he is outwitted by a woman. Doyle's literary earnings escalated rapidly. He decided to leave medicine and "to trust for ever to my power of writing."

As early as 1893 Doyle attempted to kill off his lucrative but irksome detective, though he prudently left a tiny loophole. But there were many other outlets for Doyle's remarkable energies. He wrote prolifically – he would have liked his literary reputation to rest on his historical novels, such as The White Company and Sir Nigel. He dabbled in the theatre. He played cricket, recording his sporting progress in his diary and admonishing himself to do better.

He became an enthusiastic public figure, ever ready to plunge into controversy like a literary knight errant. With mixed success, he threw his and Holmes's prestige into real-life miscarriages of justice. During the Boer War, he served in South Africa as a volunteer doctor and wrote two influential books supporting the British. He was offered his knighthood for this, rather than for services to literature. His instinct was to decline, but his mother persuaded him to accept it.

Doyle's private life plays an important part in both books. His diminutive "Mam" held the family together and remained his confidante until her death in 1920. She is by far his most important correspondent in A Life in Letters, which could almost be titled Letters to Mother. His first marriage was dominated by his wife's long struggle with tuberculosis. After her death, Doyle married a much younger woman with whom he had been romantically, and perhaps sexually, entangled for the previous 10 years

Catholicism had lost its appeal for Doyle, but as early as 1893 he joined the Society for Psychical Research. Lycett demonstrates how Doyle's interest in the esoteric informs some of his fiction, particularly the non-Holmes stories. Spiritualism exerted a greater and greater fascination and, after the Great War, it dominated his life.

What both books make clear, in their different ways, is that Doyle was far more than the man who invented the coolly rational Holmes and yet believed in spiritualism. The Irish Roman Catholic reinvented himself as the English gentleman. The chivalrous family man conducted a 10-year affair that scandalised his family. Doyle may have been credulous about fairies but he was a shrewd man of business who dealt firmly with his publishers.

For all his early rationalism and his later faith in spiritualism, his fearful side runs like a dark thread through his fiction. His first memory was of his dead grandmother. His father, a struggling artist and draughtsman, declined into alcoholism exacerbated by epilepsy; this unhappy fate haunted his son throughout his life like an inconvenient morality tale.

Both these books are indispensable to anyone with an interest in Conan Doyle. The letters reveal him relaxed and unbuttoned as never before. Lycett has written undoubtedly the best available biography. As a bonus, his Afterword reveals the occupational hazards facing a biographer when his subject's heirs have a vested interest in much of the source material.

Andrew Taylor's latest novel is 'Naked To The Hangman' (Hodder)

Conan Doyle is published by Weidenfeld & Nicolson £20 (528pp) £18 (free p&p) from 0870 079 8897

Arthur Conan Doyle: A Life in Letters is published by HarperPress £25 (686pp) £22.50 (free p&p) from 0870 079 8897