In a memoir, he wrote that his father, also named Otto Beyer, was born in a farming area in Allstedt, Germany, and was the son of a country doctor. His father studied business in Berlin and came to Baltimore in 1909. His mother was a nurse.
He was born in Baltimore and spent his youth in Towson, Hamilton and Irvington. He attended St. Joseph Monastery School and was a 1945 graduate of Mount St. Joseph High School, where he competed on the debating team. He worked nights at the Social Security Administration, then located in the Candler Building in the Inner Harbor, to help support his family.
In May 1945, he began a wartime accelerated program at Loyola College. His studies were interrupted by service in the Army as a clerk in the Counterintelligence Corps in Japan.
He left the military in 1949 and completed his bachelor's degree in 1951. He then entered the University of Maryland School of Medicine.
"I was lucky to have had the assistance of the G.I. Bill, which helped with tuition during medical school and resident training," he wrote in the memoir.
He earned his degree in 1955 and spent two years as a resident at Bon Secours Hospital. While there, he met his future wife, Patricia Ann Rowe, who was an operating room nurse. He then spent four years at the University of Maryland in surgery and urology training, working under Dr. John D. Young.
"He was the first person I met in medical school, and we remained close friends for 61 years," said Dr. Eugene Benitez, a retired cardiologist who lives Ellicott City. "He was an extraordinary man. ... He was unshakable in his convictions, and he could argue with you at length, but never with rancor or maliciousness."
He established a practice in urology in 1961 and retired in 1992. He was on the staff of St. Agnes and Bon Secours hospitals and had an office in Ellicott City.
"He was good with his patients and was well received by the other doctors," said Dr. George Bauernschub, a friend and retired pediatrician who lives in Catonsville. "He was gracious and fun to be around. He could tell a good joke and people enjoyed being with him."
Dr. Beyer wrote numerous letters to The Baltimore Sun, on topics including the Vietnam War, the U.S. Postal Service and traffic.
"To see how public transportation functions to relieve congestion, one should visit most of the modern cities of Europe," he wrote in 2002. "In London an extensive underground network does a tremendous job of relieving congestion. Here in Baltimore we are nearly a century behind in the construction of an adequate subway system."
His wife, Patricia Ann, said he was a "staunch Republican" and newspaper reader whose capacity for writing letters occasionally surpassed a newspaper's ability to print them all.
"He was very vocal about things and people knew how he felt," she said.
He enjoyed golf games at Turf Valley Country Club and other courses. Family members said he read a book a week and also subscribed to numerous magazines and periodicals. Dr. Beyer spoke German and traveled extensively throughout Europe and other destinations.
He donated his body to science.
A memorial Mass will be held at noon Monday at Resurrection Roman Catholic Church, 3175 Paulskirk Drive in Ellicott City, where he was a member.
In addition to his wife of 54 years, survivors include three sons, O. Christian Beyer Jr. and Eric Beyer, both of Ellicott City, and J. Earle Beyer of Bel Air; two daughters, Mary Pat Davis of Finksburg and Anneliese Simpson of Thurmont; a brother, John Beyer of Arbutus; and 14 grandchildren.