For all those students who struggle with their dissertations, seeing no end in sight, consider the case of John O'Brien, M.A. '89, Ph.D. '09. After more than 20 years of research and writing, 14 of them as a quadriplegic, O'Brien has finally earned his Ph.D.

After completing his Cornell M.A. in the history of architecture and urbanism in 1989 and his coursework in the Ph.D. program, O'Brien returned to Knoxville, Tenn., to write his dissertation and teach architecture at the University of Tennessee, where he remains an adjunct professor. He made field visits to the Italian Piedmont to do research on his topic -- the churches of architect Bernardo Antonio Vittone -- before he was injured in an accident in 1995.

O'Brien lost the use of his arms and legs and became housebound. When he regained some use of his arms, he resumed work on his dissertation, relying on interlibrary services at the University of Tennessee to complete his research, he said.

"Somehow I was able to maintain interest in the topic for the 20 years it took me to write the dissertation -- although, I admit, I am a little burned out on it now, and I am [now] busy with other scholarship unrelated to it," he said.

His 877-page dissertation -- "The Openwork Dome as Sacred Theater: Illumination and Illusion in the Centrally Planned Churches of Bernardo Antonio Vittone" -- was approved and accepted May 5, O'Brien said. It includes 543 pages of text, a bibliography and 246 images in an appendix.

"I first learned of Vittone's churches as an undergraduate student at Rice University while taking a course on Renaissance and Baroque architecture," said O'Brien, who also has undergraduate degrees in art history, architecture and medieval cultural studies. "I wrote a paper on the topic as a graduate student at Cornell for Christian F. Otto's course on Baroque architecture, and another paper on the topic for Professor Otto's graduate seminar on architectural theory."

O'Brien will not be able to attend commencement this year, but he is satisfied with his accomplishment.

"It feels great, and I'm especially happy that I was able to complete the dissertation as I had envisioned it from the start, and without compromise," he said.