Le Corbusier's sketchbooks

He was offered both money and a site. Plump congregations asked the Genius to build them their own version of Ronchamp, his cathedral masterpiece, and even handed him ample budgets and projects laid out like the fine frame of a puzzle.

The Genius had only to fill in the pieces. Naturally, he said ''no.''

''I don't want to make a church,'' Le Corbusier said. ''I have made Ronchamp.''

Then there came a time and a church that had no money. Even the site was a problem, a ''jerry-built and unsanitary old fabric,'' one source says.

So the architect said ''yes.''

''It would be a nice drama,'' his assistant, Jose Oubrerie, recalls. ''And he started. He needed drama to make architecture.''

That was in 1960. Today, two decades later, the drama is still in progress. It is Act II at the church of St.-Pierre de Firminy-Vert, and Oubrerie's mission is to finish the play.

Some say it will be Corbusier's final masterpiece. Others wonder whether the ''signature'' will be shared by those who finish the remaining half of the building if the money is raised.

However far the end product may edge away from the master's intent, the show organized by his assistant and the University of Kentucky presents an immensely pleasurable project. The drawings - some sold to raise $2 million of the needed the aficionado as much as the working-class community the church serves.

The traveling exhibition - tentatively scheduled at Pittsburgh Plan for the Arts in January and Rice Institute, Houston, and the University of Texas at Arlington thereafter - and the missionizing protege give insights on the architect himself.

A catalog amplifies the trials Oubrerie faces at Firminy, and Mayor Eygene Calufius-Petit makes a plea: ''Marseilles has its Radiant City. Arbresle has its convent, Ronchamp its chapel, Saint-Die its factories for the modern epoch, Poissy its Villa Savoye. But in Firminy, Le Corbusier built the House of Culture and of Youth, the Olympic stadium, a Unite d'Habitation, and his last work, the church of Firminy-Vert, which is still under construction.''

The church, writes the mayor, has known many difficulties: ''Indeed, all difficulties imaginable.''

Described as an ''imperious monolith'' set in a water channel, it earned only a brief commentary from the architect himself. The church at Firminy ''is, by virtue of its terrain, located at the bottom of a valley,'' Le Corbusier observed. ''It consists of a hyperbolic-paraboloid shell, and, after Ronchamp and La Tourette, represents a third, new type of church.''

In proseletyzing on the master's behalf, Oubrerie is more expansive. He swings his crayon across panels of brown paper to show the simple, yet sweepingly monumental, structure to an audience at Harvard University's Graduate School of Design, as he has elsewhere.

''To Corbusier, the church was interesting because you could make experiments and maybe reach results using light,'' he goes on.

The windows that sent the sun like piercing gems through the windows of Ronchamp trip across Firminy, too, in his presentation. The grandness of Ronchamp's rising setting makes a contrast with the scooped-out site at Firminy.

Even more compelling is the sense of the enigmatic shaper of the Modern Movement that Oubrerie and the exhibition reveal. The immediacy and improvisational quality of the drawings on view - and the capacity of the program for Firminy to grow and improve under his seeming free but firm hand - underscore the mix of thought and spontaneity.

Oubrerie describes Corbusier's on-site method of work as ''a last-minute architecture.'' The architect himself called it the product of ideas set ''inside my memory'' and given time to ''marinate.''

The nature of these visual ideas and sources from the 20th century's preeminent architect have also emerged in a more scholarly project. Fifty years of Corbusier's jottings and germinations are being reproduced in four volumes of his 73 sketchbooks by MIT Press and the Architectural History Foundation. In a costly ($125 apiece), limited (1,200 copies) edition, the publishers have produced four volumes - 1914-48, 1950-54, 1954-57, and 1957-64 for release by next spring.

Drawn from the fragile material at the Fondation Le Corbusier, the collection from his sketchbooks lavishly unfolds some drawings that are architectural and many that might have come from the hand of the architect who signed his artwork by his birth name, Jeanneret.

Vol. I, released in June, seems to dote on the architect's works as much as it displays them. There are pages that are gray to the point of invisibility, sketches with stamps and dates that need a cryptographer, French captions wanting a translator, and copies of pages of too-pallid writing.

Obviously, the man is worth the reverence. And myriad pages have an independent charm - from an enchanting color sketch of a hat, pipe, and flowers to the fluid curves of hard-edge rowboats; from nudes and shells to the notations of a more architectural nature.

In a still more intimate fashion, the traveling show of these ''Fragments of Invention'' - at the Carpenter Center here through Dec. 13 - is a poignant testimony to the humanity of the architect.

Almost 20 years after the architect's passing, the new communication from his hand-size sketchbooks emphasizes both his receptivity to all forms of life and his capacity to capture and translate their essence into architecture.

Although some of these sketches, enlarged from these books, are artifacts or artworks in themselves, it is clear that the notations of this restless doodler mean more as a visual autobiography than as art.