In Paris, her contact with the Surrealist group – which had regrouped at the end of the war, after André Breton’s return from exile in America – led her to rethink the foundations of her painting.

Setting aside the rapid, sensual brushstrokes she had learned from her uncle Filippo de Pisis, she began to produce small-format paintings in a lucid, precise figurative style, applied, however, to dreamlike and fantastical scenes. Her canvases are populated with insects, toads and objects gathered on the beach: stones, pebbles, driftwood worn by the tides, roots (which she renamed “mandrakes”) that, hugely enlarged and set in the emptiness of metaphysical landscapes, take on the appearance of unsettling apparitions.

After 1956 – a dramatic year for the artist, marked by the death of de Pisis – Bona’s enchanted settings are emptied of human and animal presences. Only the landscape remains: a primordial landscape, arid and sun-scorched, rendered in fiery hues and inspired by the valleys and hills of Upper Egypt, which she had visited the year before during a journey lasting several months.

Around 1959 Bona’s painting had shed every last trace of figuration. The artist began to work with earth, sand, powders, glues and stucco, applying them mostly with a palette knife and incising them with the end of the brush handle. The thick, rough, granular matter, scored and split by cracks and fissures, becomes the protagonist; the palette is reduced to the basic ranges of blacks and browns, lit by dramatic flashes of brilliant white and red.

Her turn to abstraction did not stem from a search for “pure” form, free from any association with reality, but rather from a violent need to express herself. Although the canvases of this period were often inspired by photographs of peeling walls taken by the artist herself, Bona described her creative process in terms of Surrealist “automatism” – a surrender to the flows of the unconscious that led her to paint spontaneously and intuitively, without rational filters.

Only once a work was finished did the artist recognise meanings in it, to which she alluded in the title: in Prehistory of Venice (1959), for instance, an arc of white drips recalls the bridges of the lagoon city; in Flamel au fourneau (1961) silver and gold evoke the processes of alchemy (Nicolas Flamel was a famous 14th-century alchemist), with which the artist explicitly associated her own painting: “My research is alchemical,” she writes in her autobiography. “I want to make gold out of excrement.”

Mexico – “the most surrealist country in the world”, according to André Breton, and a destination for many leading figures of the movement from the 1930s onwards – was destined to leave a deep mark on Bona’s life and work.

The artist travelled there with André in 1958 for a long stay, during which she held an exhibition at the Galería Antonio Souza. Guided by the poet Octavio Paz, the couple toured the whole country, visiting pre-Hispanic archaeological sites and meeting leading figures of the local art scene connected with Surrealism, such as Leonora Carrington, Alice Rahon, Wolfgang Paalen and Juan Soriano.

The country’s culture and atmosphere – rich in violent contrasts, marked by the untamed vitality of nature and the animal world, as well as by an obsessive presence of death – fascinated Bona. Their influence can be seen in a group of works made between 1959 and 1961, such as The Apogee of the Serpent, with its suggestion of telluric depths inhabited by reptiles; Le Grand Luisard (slang for the sun, which in the painting shines over a sexualised landscape); Los huesos florecidos, in which the sinister presence of the skull and crossbones is combined with the brazen sweetness of the palette; or Labyrinth, whose genesis Bona described in a letter of 1961: “I tried to work away furiously at a small canvas, but no subject would settle on it. I felt deeply disheartened to find that I was overwhelmed only with a great emptiness (…) and then, like an animal, with my nails I traced, or rather dug (…) a stupid line that no one knows where it comes from or where it goes, but that turns and turns again, as if it were in the hall of mirrors of a fair.”

In 1958, while tearing up an old suit of her husband’s to make rags, Bona was struck by its inner structure – a padding of white cloth, what in French is called l’âme, the soul. The artist traced back to this episode the origin of the compositions of torn fabric, sewn and applied to canvas, that would from then on become her favourite medium. “Since a woman can’t do painting, I’ll do couture,” she later remarked ironically.

This intuition put her perfectly in tune with developments in contemporary artistic research: assemblage (a three-dimensional version of collage) was in those years the focus of attention in both Europe and America. Among the masters of the technique were artists close to her, such as Jean Dubuffet, Alberto Burri and Enrico Baj.

In her early assemblages (made from men’s suits) the original shape of the pieces of fabric can still be made out, as in La vague à l’âme and Taureau nuptial (1958). Later the material, now drawn from salvaged fabrics, becomes more fragmented, and the zigzagging, at times convulsive, pattern of the stitching – done on an old treadle sewing machine – helps to set the rhythm of the composition (Le déjeuner sur l’ombre, 1962). Initially semi-abstract, the images gradually become more clearly defined, eventually including portraits, while taking on an increasingly visionary character.

On her return from her second stay in Mexico in 1966 – which followed a journey of several months through India, Nepal, Afghanistan and Ceylon – Bona once again reinvented her work. Acrylic paint, which she had begun to use instead of oil, led her to lighten and enrich her palette, which now bursts into a phantasmagoria of colour. A strong linear grid structures the images, outlining their facets of colour as in a kaleidoscope.

For a brief moment her canvases are crowded with detail; they become delirious narratives, dense with symbols, in which the human, the vegetal and the animal intertwine in ways at once seductive and threatening.

The key works of this phase, Histoire de famille and Genèse mexicaine (both 1967), evoke a mythical universe steeped in eroticism and cruelty, close to the world of the paintings of Francisco Toledo, the Mexican artist to whom Bona was close in these years. The 1968 self-portrait and the almost contemporary portraits of André and of Toledo, likewise highly charged with symbolism and painted in heightened, hallucinatory, almost psychedelic colours, bring this interlude to a close.

Giorgio de Chirico’s Metaphysical Painting – with its incongruous juxtapositions of very different objects, its unsettling views of cities empty of human figures and its sudden shifts of scale – had been one of the sources of Surrealist art in the years between the wars.

Bona had looked to de Chirico’s example from a very young age: her first commissioned painting, made at the age of nineteen, was a still life with a metaphysical flavour, and her relationship with her uncle Filippo de Pisis – one of the protagonists of the metaphysical season in Ferrara in 1917 – later strengthened her interest in the movement.

It is nonetheless rather surprising that in the 1970s, after having gone through phases of artistic exploration far removed from de Chirico’s painting, Bona decided to return to it with a series of paintings that explicitly quote its iconography and style. In fact, however, the lens through which she views Metaphysical Painting is once again highly personal: for her it is a way of revisiting crucial moments of her own life and situations with a strong emotional charge as revealed by works such as Toledo the Rooster, alluding to Francisco Toledo, or Le Céleste Empire in which the blue shadow outlined against a typical de Chirico-style monumental setting is that of de Pisis.

In the 1970s the motif of the snail – her totemic animal and a key figure in a Surrealist bestiary that also includes toads, snakes and chameleons – took on a central role in Bona’s work. The snail, in which the artist recognised herself and with which she identified , holds several meanings: “a lunar and lunatic animal, it symbolises movement in its permanence”; as a hermaphrodite, it is a symbol of the androgyne, but it also evokes a sense of attachment to home, and hence stability. Furthermore through the form of the spiral it is an image of the universe: Bona declared that “by embracing the forms of the spiral, it is the universe itself that I embrace.” Finally, the animal’s withdrawal into its own shell conveys the idea of a turning inward and a rejection of the outside world, with its materialist and productivist logic – a prelude to the attainment of full spiritual fulfilment.

In the works of her last period, human figures – especially female ones – take on the features of the snail through a process of deformation that radically alters their appearance, in a metamorphosis at once repellent and mysteriously fascinating. These hybrid, distorted, disjointed bodies point to a reflection that Bona developed in confronting mental distress, which during these years led to her being hospitalised several times: a fate shared by other women Surrealists, from Leonora Carrington to Unica Zürn

The 1990s, which opened with André’s death in 1991, were for Bona a time of introspection, recollection and reconsideration of her own personal history.

The autobiographical theme, always present in her work, now gains particular prominence. Alongside compositions centred on the couple and family life (Bona and André, 1990; The Holy Family, 1997), self-representations multiply: sometimes in a symbolic way, as in La femme-montagne, where the identification of woman with nature – a recurrent stereotype in male culture – is overturned into a powerful self-assertion, underlined by the oversized gold signature; or in Ma main, a hand whose fingers have eyes, a metaphor for the artist and her grasp on the world. At other times they are explicit self-portraits, such as Bona à Mexico, in which the artist’s face is frontal and geometricized, fixed and static like an icon, or the 1994 Self-Portrait, which takes up an earlier, youthful one from 1956 while breaking down its elements, giving us the image of a complex subjectivity, by turns strong and assertive.