Double dealer in her prime

<i>Aiding and Abetting </i>by Muriel Spark (Viking, &pound;12.99, 192pp)

In her long writing career, now spanning over half a century, Muriel Spark has produced a unique body of work. Rightly regarded as one of the most innovative writers of her generation, she has also retained a popular appeal - not least because of the film and theatrical versions of The Prime of Miss Jean Brodie. Although many wish to claim her - she is equally well known as a Scottish writer, Catholic convert and poetic modernist - her greatest achievement is to defy all categories. While some think of her as an unchanging moralist, others consider her playfully anarchic. Her fictions are tantalising precisely because they are able to sustain such radically different readings.

In her long writing career, now spanning over half a century, Muriel Spark has produced a unique body of work. Rightly regarded as one of the most innovative writers of her generation, she has also retained a popular appeal - not least because of the film and theatrical versions of The Prime of Miss Jean Brodie. Although many wish to claim her - she is equally well known as a Scottish writer, Catholic convert and poetic modernist - her greatest achievement is to defy all categories. While some think of her as an unchanging moralist, others consider her playfully anarchic. Her fictions are tantalising precisely because they are able to sustain such radically different readings.

Aiding and Abetting, her 21st novel, is in many ways a subtle summation of her work. On the one hand, it harks back to her early didactic tales such as Memento Mori (1959) or The Girls of Slender Means (1963). On the other, it recalls more anarchic books such as The Abbess of Crewe (1974) or The Takeover (1976). Spark's abundant gifts are such that she refuses to rest on her laurels. Always shifting in time, her fiction has encompassed Rhodesia, Edinburgh and Jerusalem and has rotated between London, New York and Rome. But no one time or culture has been allowed to delimit her imagination. When her novels become overly impersonal, as in The Driver's Seat (1970) or Not to Disturb (1971), she writes autobiographical works such as Loitering with Intent (1981) or A Far Cry from Kensington (1988).

The self-questioning which characterises her best work is especially apparent in Aiding and Abetting. In effect, it contains two versions of her fictional universe. The novel begins sensationally with the figure of Lord Lucan, wanted for bludgeoning his children's nanny to death in 1974, visiting a psychiatrist, Dr Hildegard Wolf, in her Parisian offices. While this is startling (the actual Lucan has famously never been captured and is thought to have died), it is compounded by the bizarre fact that Wolf already has a "Lord Lucan" as a patient. What's more, it turns out that Hildegard also has a whole other history.

Hildegard is in a long line of wilfully intelligent Spark heroines, but unusual in having a completely different past identity. Born Beate Pappenheim on a pig farm in rural Nuremberg, she managed to escape extreme poverty by becoming a "fake stigmatic" who tricked thousands of impoverished Catholics into sending her their hard-earned wealth. After changing her identity, she became a celebrated psychiatrist. It is probably no coincidence that her name is literally a beatification of Bertha Pappenheim, Freud's "Anna O" and one of his most famous patients.

As with Hildegard's dual self, the two Lord Lucans indicate the extent to which everything in Aiding and Abetting is doubled and redoubled. Spark's fiction has always been fascinated with doubles, and the act of doubling is closely related to the act of writing. The double vision of Dougal Douglas or Douglas Dougal in The Ballad of Peckham Rye (1960) announces not only his spiritual role in Peckham (going beyond the pervading materialism) but his eventual vocation as a novelist. Jenny Gray and Sandy Stranger in The Prime of Miss Jean Brodie (1961) also listen to Brodie with sceptical "double ears" which allows Sandy, a would-be author, to see beyond the teacher's mythomania. Such doubleness is at the heart of Spark's fiction-making, as well as her sense of virtue.

On one level, Aiding and Abetting is a straightforward morality tale which compares the attractive Hildegard with the distinctly reptilian Lucan. But there is something strangely plausible in Lucan seeking her out even though he knows her to be a bogus (albeit successful) psychiatrist. They have a good deal in common.

Both figures are fugitives from the law. They have both been on the run and have escaped justice due to the misplaced loyalty of "aiders and abetters". Both have also been forced to assume alternative identities (Spark's Lucan undergoes plastic surgery). Beate Pappenheim's blood ritual, in particular, is dramatically related to Lucan's murder victim, Sandra Rivett, whose blood "got everywhere. Pools of it". Beate, the holy stigmatic, who is also based on an actual person, imitated one of the five wounds of Christ by covering herself in menstrual blood.

Spark's fiction invariably teases out the differences between superficially similar figures of good and evil. Hildegard and Lucan are both in the "blood business" together. Not unlike the ideal novelist, the "Wolf method" of therapy combines a God-like authority with Hildegard's distinctive voice (she speaks continuously to her patients for the first three sessions). Lucan, in contrast, is a bad writer in aesthetic and moral terms, who believes that it is his "destiny" to kill his wife. His murderous plot "leaked" like a "blood-oozing mailbag".

What stops Aiding and Abetting from becoming overly moralistic is the exuberance of its story-line - which encompasses Central Africa and the Scottish Highlands as well as London and Paris - along with an engaging playfulness. The "facts of blood" are not reduced to mere biology but given a gloriously expansive set of meanings. As Hildegard's lover says of her past spoof activities: "What else should a woman of imagination do with her menstrual blood?". While Hildegard's imagination is able to transform her circumstances, Lucan, utterly devoid of imagination, fails to abolish the "blood" and "mess" which he had unleashed in 1974.

Spark's ability to see everything with double eyes leads, at its best, to a generosity of spirit and ingrained pluralism. For this reason, Hildegard's fear of the past is countered by the everyday pleasures of making art. In an extraordinary ending, set in a fictitious country in Central Africa, everything in Aiding and Abetting is turned on its head. Until this point, Spark had set up the fundamental distinction between blood as mere matter (Lucan's daily diet of lamb chops) and the transfiguration of the blood of Christ.

But when looked at from an African perspective, this return to Catholic first principles is given a completely different tenor. That Spark has managed to create such an astonishingly ambitious work in her eighties shows, more than anything else, the enduring power of her artistic gifts. Let us hope that there are many more books to come from this remarkable novelist.