JOSEPH ALLEN STEIN, the architect, who died at the age of 89 in Raleigh, North Carolina, on October 6, was a major icon, quiet and self-effacing. Born in 1912 in Omaha, Stein studied under the Finnish architect Eliel Saarinen at the Cranbrook Academy in Detroit, Michigan, in the early 1930s. This legendary campus, designed by Saarinen and filled with sculptures by Carl Milles, the Swedish sculptor, influenced Stein's design philosophy. The American midwest was the centre of a regional modern movement influenced by the work and teachings of Frank Lloyd Wright and Louis Sullivan. The design approach developed was very different to the Bauhaus modernism then taking hold in Europe, which arrived on the American shores with the immigration of Walter Gropius, Mies Van der Rohe and others just before the Second World War. The Bauhaus tended to be insensitive to local culture and materials of building, and advocated a hard edged design philosophy using industrial elements. The influence on Stein, on the other hand, was a view which incorporated organic materials, brick, stone and wood, with a willingness to decorate through texture and volume, yet retaining a simplicity and human scale. Stein moved to California in 1938 to work with the Austrian Richard Neutra, who became another great influence. Neutra's spare, elegant houses were carefully sited in the California landscape with large glass vistas blurring the boundaries of interior and exterior. He also married Margaret the same year, and she became not just a companion, but a crucial design colleague. Moving north to San Francisco, Stein became a vital part of the design scene in the Bay Area working with architect John Funk and landscape designer Garret Eckbo, eventually opening his own office. Living in Mill Valley, Joe Stein designed a number of houses which became recognised as major examples of the 'California School'. As a team, they had planned and designed a large cooperative residential community at 'Ladera' near Palo Alto, which had idealistic social aims of simplicity surrounded by landscaped beauty in the post-War peace. Unsuccessful in raising financing, Joe and Margaret Stein moved to Europe in the early 1950s. Richard Neutra, who had been invited by the Government of West Bengal to be an adviser, proposed Stein's name as head of the newly-formed Architecture and Planning Department at the Bengal Engineering College in Calcutta. Accepting the invitation, Stein arrived in 1952, little realising that he would stay on.

He has written of his initial reaction: "It was a very stimulating, extraordinarily interesting time, India was almost newly Independent. It was like coming to the United States when Thomas Jefferson was alive, something like that. Nehru was Prime Minister, who was an outstanding man. He had his flaws - many great men are flawed, maybe all human beings are flawed. But he was an extraordinarily beautiful and intelligent man, and he cast an aura over India that was very attractive. At that time the memory of Gandhi and Tagore was fresh and bright in India, and had very much influence among the students. So students were very attractive people to work with... they were idealistic and dedicated."

Stein arrived in India already formed as a mature and self-assured designer and planner and immediately plunged into the major project being undertaken in West Bengal - the Durgapur township, designed with Benjamin Polk, an American architect living in Calcutta. (It was also there that he became a close friend and colleague of my father Habib Rahman, who had also returned from the U.S. with an American architectural degree, an association which makes this tribute a personal one.)

Joe (and my father) moved to Delhi in the 1950s, Joe to set up private practice and my father to join the Central public works department. After Independence, both worked in that magic moment literally building the new India right at its heart, New Delhi. Both Joe and Margaret were very quiet people, yet they held very strong and idealistic beliefs. Few people know that they had left California after the War, disillusioned by the new McCarthy era. In a way, the India that the Steins found themselves in held all the positive hope for a great new society - socialist, pacifist and egalitarian, ideals that were dear to both and lay at the core of both their design philosophy and their vision of their own life's journey. Ideal as companions to each other, my memory of them as a little child is of a couple of such grace and gentility, they were calming like yogic gurus. The full glow of the 'Nehruvian enlightenment' was influencing the emergence of an entire new, modern India. While other famous architects were coming and working in the country then - Le Corbusier, Louis Kahn, Charles and Ray Eames, Edward Durrel Stone, Maxwell Fry and Jane Drew, Stein differed from them in that he had made India his home and sought to be actively involved in the making of the new society. In Delhi, our two families would spend every weekend exploring every ruin and village. This was a living discovery of the great Sultanate architecture of Delhi, in the days when all the sites were still near little villages surrounded by blazing yellow mustard fields in winter. Both Joe and my father developed a fascination for the traditions of Delhi building and its effect on Joe could not be clearer than in the India International Centre (IIC). The surfaces and materials Stein used: local stone, cast concrete jails, blue and green ceramic tiles as highlights, were an updating of the Sultanate architecture of Delhi, which Stein had learned to love and admire through weekly exploration.

It was in his New Delhi buildings - notably the Triveni Kala Sangam arts complex (1957-77) and the ICC (1959-62) - that his full design personality emerged. Both were immediately distinguished by their elegant formal spaces, beautifully muted by covered walkways, extensive planting and landscaping and their meticulous detailing.

"Two things have essentially guided my work. One is what you might call an interest in and search for an appropriate modern regionalism. I would put equal emphasis on both words, 'regional' and 'modern', because regional without modern is reactionary, and modern without regional is insensitive, inappropriate. The second one is to seek the character of the solution in the nature of the problem, as much as one possibly can," Stein had said.

What Stein achieved, in a way, was to bring his 'California Modern' into an Indian context, altering his design vocabulary by the observation of Indian life and construction systems. In Delhi, surrounding the IIC he continued to build a series of buildings which have become landmarks - the Ford Foundation, the United Nations, the World Wide Fund for Nature and most recently the huge India Habitat Centre. If anyone could match the Lodhis and their architecture, it is this series of buildings built by Joe through the 1960s and 1970s. The sensitivity to detail, construction, material and texture of the buildings were matched by Margaret's equally careful attention to the furniture, the textiles, the plants and the seasonal flowerings of the bushes and trees. Joe's legacy is that of living architecture - human in scale with spaces which soothe and inspire. It is no surprise that four decades of India's cultural life have been nurtured at the IIC and at the Triveni Kala Sangam.

Less known is the stunning American School (1960-70) set in the rolling landscape of Chanakyapuri. Here Stein used the existing landform and rocky outcrops and designed his buildings to weave in and out of the space, incorporating the rocks in surprising juxtapositions within the corridors and classrooms. Not many people have seen the equally remarkable factories that Joe designed for Escorts. His complex trussed roofs are classics of 20th century architecture and are a testimony to his design discipline and collaboration with engineers and contractors, as well as his adaptation of local technologies to highly sophisticated design experiments in what would otherwise be mundane industrial environments. In Delhi, the huge domed exhibition hall in the Trade Fair complex was the last of this series.

Margaret Stein had worked for many years with the Tibetan refugees when they crossed into India in the 1960s, and Joe had an abiding love for the mountains, designing buildings in both Kashmir and Bhutan. Joe's interest in larger environmental issues and the looming crisis of de-forestation in the Himalayas led him to become an advocate of sustainable development in ecologically fragile areas of the country. He helped organise a UNESCO (United Nations Educational, Scientific, and Cultural Organisation) conference on the protection of the world's mountain environments in 1973.

Being an essentially shy man, Stein did not push to publicise his work or publish as widely as he should have. He preferred to have his work speak by example, and also showed by example how to live a complete life honest to one's own beliefs. His old age was marked first by the loss of Margaret, and then by infirmity which was very difficult to watch. But perhaps saddest of all was the collapse of his professional partnership and the bitter aftermath. But he was well served by an excellent book on his work, design philosophy, teaching and writing, by Stephen White: Building in the Garden: The Architecture of Joseph Allen Stein in India and California published by Oxford University Press in 1993. Stein was awarded the Padmashri in 1992, was honoured by the JK Cements award and the University of Madras conferred an honorary degree on him, the only architect to be so honoured. The enduring impact of Stein is his built legacy - which embodies the humanist and social idealism of this design seer. India is the richer for his building in our garden.