The sculptures of Imogen Stuart embellish churches and public spaces all over the State. Still working as hard as ever, she is the most versatile and productive of living Irish sculptors, yet her work remains curiously underrated

Imogen Stuart has been steadily active in the Irish art world for half a century, and for that reason there is a tendency merely to take her for granted rather than to give her large, varied output its rightful due. Above all a craftswoman-sculptor, she has worked in wood (her favourite material), stone, bronze, steel, concrete, copper, even cement - a technical versatility that few, if any, Irish sculptors could equal. Much of her work has been for the Catholic Church, but it can also be seen in public parks and squares, in (or rather outside) at least one Dublin shopping centre (Stillorgan), at schools and colleges, hospitals, and so on. This is apart from the many smaller works in private collections and a handful of portraits, including one of Mary Robinson.

That makes for a fulfilling lifetime's work, and in her early 70s she is still highly active and has various projects on hand. The large exhibition - technically not a retrospective, but close to being one - which opens on Friday is mounted in the RHA Gallagher Gallery. This is fitting, since she has been a pillar of the RHA for at least two decades and became its professor of sculpture two years ago. She is not, however, an academic of the old order, though the rapid changes in sculpture over the past 30 years have made her style look relatively conservative.

To call her a traditionalist may sound tame and limiting, yet Imogen Stuart's work does have strong roots in tradition - though a German tradition more than any specific Irish or Anglo-Irish one.

She was born in Berlin, the daughter of a leading art critic, editor, cultural historian, novelist and translator, Bruno Werner. Her father was partly Jewish and when the second World War came, he was banned from any branch of the armed forces, though he had fought honourably through the previous world war in a Saxon infantry regiment. Werner's high-profile arts magazine, die neue linie, folded under wartime pressures, and eventually he was forced to lead an underground life, so that his family saw him only rarely. During the Allied bombing of Berlin, Imogen, her mother Katherina and her younger sister Sibylle were twice evacuated - to Bavaria and then to Klosterneuberg, on the fringe of Vienna.

The war ended with the family split in two: Imogen and her father in Bavaria, where they were liberated by the Americans; the mother and younger sister in Austria, where they were liberated by the Russians. The Russian soldiers were busily raping any eligible female within range, but somehow Katherina and her daughter escaped in a cattle-truck and the family were reunited in Bavaria.

Bruno Werner was rehabilitated officially after the long nightmare of the war years and served brilliantly as a cultural attaché in Washington, where he brought German art, German actors and German musicians before the American public.

It was in the immediate aftermath of the war, with cities and towns in ruins and semi-starvation almost everywhere, that Werner approached a respected older sculptor, Otto Hitzberger, whom he had known and befriended in Berlin. A leading teacher as well as a notable artist, Hitzberger had lost his post under the Nazis and retired to his native town, Garmisch-Partenkirchen, where he lived quietly with his wife. He agreed to take on Werner's 18-year-old daughter as his pupil, so she began a five-year apprenticeship with him which, she admits, was the shaping influence on her career.

Later they were joined by a young Irish sculptor, Ian Stuart, who also studied under Hitzberger and in 1951 became Imogen's husband. They settled in Laragh, near Glendalough, along with Stuart's mother Iseult, the daughter of Maud Gonne. Iseult's husband, the novelist Francis Stuart, had gone to Germany before the war and did not return until long after his wife's death.

Imogen and Ian had three daughters, the second of whom, Siobhan ("Pussy"), was killed in a car crash in 1988, leaving a small family of three boys. By then the artist parents had long separated, and Imogen was living at Sandycove in south Dublin. She still lives there, with a studio just up an adjoining lane.

Ian Stuart was a very gifted sculptor, probably the finest of his generation in Ireland, and for a while Imogen worked in his shadow. Soon, however, she got various commissions in her own right and also showed at annual group exhibitions such as the RHA, Living Art, the Oireachtas, Independent Artists. She and her husband held a joint exhibition in 1959 at the now vanished Dawson Gallery, but, strange as it may seem, Imogen's first solo exhibition was not until 1992, when the arts group, Alternative Entertainments, courageously mounted one at the Square in Tallaght, Co Dublin. Busy with commissions, some of them very large, she had little time left to work for private galleries and only in the past few years has she exhibited her smaller pieces at the Solomon Gallery.

CHURCH commissions were for years her bread and butter; they include the big metal crucifix in Armagh Cathedral, the stations of the cross at Ballintubber Abbey in Co Mayo, the much-admired stations in Our Lady of Mount Carmel at Firhouse, the altar of Liam McCormick's innovative church at Burt in Co Donegal, the bronze doors of Galway Cathedral and those at Newcastle Church of Ireland in Co Wicklow - to mention only a random handful among many.

She learned how to work alongside architects, to assess the potential of a site or indoor space and to suit her style to it, how to design individual fitments and church décor. Much of this obviously could not be made or carried out by a single person, which led her to employ the services of craftsmen in other fields, such as steelworkers and weavers. Sheer physical energy and a basically optimistic temperament were essential assets in this often gruelling schedule, which consumed most of her middle years.

Her favourite material, however, remains wood, and she talks enthusiastically and knowledgeably about the different types, grains and characters of it she has worked in over the years. One of her best-loved pieces is the large Pangur Bán, originally created for a shopping centre but later moved to University College, Dublin. The more recent Window on the World (1991) has yet to find a resting-place, though I see it as one of her most original creations.

Of her works in metal, the Tree of Life in Glasthule Church is another familiar work, but her remarkable Tree of the Seasons has never yet been cast full-scale and the small version of it remains in her studio.

The small sculptures include many bronzes and some superb woodcarvings, works much sought-after by collectors. My own wish is that as the pressure of big-scale commissions gradually eases, she will produce more of these, since they include some of her most personal inventions and show the intimate, lyrical and humorous aspect of her talents.

German and Irish Romanesque, Continental Gothic, Celtic High Crosses and metalwork, primitive art, proto-Modernist sculptors such as Barlach and her own teacher, Hitzberger, have laid the foundations of her style, which is a unique fusion of all these. The most versatile and productive among living Irish sculptors, she is also in many respects the most underrated.

•A large exhibition of Imogen Stuart's sculpture will open at the RHA Gallagher Gallery on Friday

•Brian Fallon's book, Imogen Stuart, Sculptor, is published by Four Courts Press