In this glittering array of essays, Muriel Spark writes:

"Before I became a novelist I was a poet and literary critic." To a degree, she juggled forms and genres to the end of her days, but long before then she had become embedded in the public imagination as the author of The Prime Of Miss Jean Brodie, as near perfect a novel as we are ever likely to see. That is understandable but it is also a matter of regret, for Spark - a Catholic convert with a Calvinist's work ethic - was like a never-ending firework display, producing a body of work that included 22 novels, innumerable short stories, poems, plays, criticism and autobiography. She even wrote for children.

As this book attests, her curiosity about life and literature was rapacious. It has been adroitly assembled by Penelope Jardine, her long-time companion, who in 1975 invited Spark to her then near-derelict house in the Tuscan countryside to finish a novel - The Takeover - that was proving troublesome. "I moved in for a few weeks and have remained ever since," she wrote. When Spark died, in 2006 at the age of 88, she was buried in the churchyard she could see from her study window through the olive groves.

In her preface, Jardine relates how in an interview in 2003 Spark said she intended to write another volume of memoirs. She once said the same to me but I never felt her heart was in it. While the past was of interest to her, it did not consume her. She was always looking forward, to the next novel or story or poem, that which was truly creative: "the idea for a new novel," writes Jardine, "nearly always crept into her dreams and devoured her attention."

The Golden Fleece has five sections: Art And Poetry; Autobiography And Travel; Literature; Religion, Politics And Philosophy; Publishing History. In all of them Spark's voice - direct, serene, unsentimental, candid, critical - comes across as clear as a bell summoning the faithful to worship.

Throughout her career there were several constants. She would never, for instance, lose an opportunity to acknowledge the influence of the Border Ballads. The one Scottish writer with whom she felt a special kinship was Robert Louis Stevenson. Remarking on his "attachment to the strange, the sinful and the misplaced among humankind", she could have been talking about herself.

She also had a special affinity with writers such as the ill-fated, short-lived Bronte sisters and she was especially proud - as well she might be - of her own biographical study of Emily Bronte. The modern writers she most admired were those with transcendent style. Proust's roman fleuve was a book she knew intimately. Here she recalls his interest in hats, one she shared.

She was also drawn to Georges Simenon, in particular his romans durs. She thought him "a truly wonderful writer" who would work himself into a "state of grace or trance" before he wrote. Like hers, his books were miniature masterpieces, saying no more than was absolutely necessary. As one reads a novel by Spark, one is never tempted to reach for a blue pencil. What a contrast with today's lardy products.

Religion was as important to her as literature. Cardinal Newman's Apologia Pro Vita Sua, in which he explained his conversion to Catholicism, was formative and reassuring. She found the Book Of Job enduringly fascinating and returned to it often. Did she identify with Job, who "cannot understand why God has afflicted him with a series of misfortunes"? Perhaps, though I would never have dared suggest it to her lest she think me mad. Evil, however, was an essential ingredient in her novels. Considering Hell, she wrote: "It is a place where I would like to go and come back to write a book about."

If all of this sounds rather grim, I apologise. For, as Jardine is at pains to point out, Spark's first aim was to give pleasure. Her novels, while undoubtedly serious, are always infused with joie de vivre and told with brio. That is evident, too, in these essays. Ignorant myth-makers routinely claimed she was a recluse. Nothing was farther from the truth. She loved to journey far and wide, usually by car, to see a painting - Piero della Francesca's Madonna del Parto at Monterchi was a favourite - wander round churches, dine in a restaurant or visit friends. She was an ardent people watcher and was never happier than when sitting "in a trattoria listening-in to their talk, imagining the rest ..." Travel, she believed, was essential to fire up the imagination. Hence one of her repeated phrases: "There by the grace of God I go on my way rejoicing."

Alan Taylor, Meaghan Delahunt and Zoe Strachan will discuss Muriel Spark's Finishing School For Writers this afternoon at 3pm at Aye Write!