Horst Friedrich Ungerer, 73, an economist and former assistant director of the International Monetary Fund, died July 24 of heart disease at his home in Bethesda.

For the past 40 years, Dr. Ungerer was recognized as a leading authority on international banking and financial policies, which he helped shape through his writings and his position at the IMF. His acclaimed book "A Concise History of European Monetary Integration: From EPU to EMU" (1997) is the standard work on the subject.

His international banking career began in 1959, when he joined the Deutsche Bundesbank in his native West Germany. He worked there until 1965, when he first joined the IMF and moved to Washington as alternate executive director for West Germany.

He returned to the Deutsche Bundesbank in 1968 as head of the department of European affairs, helping to establish economic and monetary policies for Europe.

He rejoined the IMF in 1970, in charge of Belgium, France, Luxembourg and the Netherlands. He had a key advisory role at the IMF from 1973 to 1980, when he was named assistant director.

He led IMF teams in Austria, Ireland, Finland and Surinam and wrote many articles on European monetary and banking policies.

After retiring from the IMF in 1991, he taught at American, George Mason and Duke universities, as well as at many universities and economic institutes in Germany and Italy.

Dr. Ungerer was born in Stuttgart, Germany, and received undergraduate and doctoral degrees in economics from the University of Tubingen.

In addition to his work as an economist, he had many cultural interests. He enjoyed many kinds of music, from classical and baroque to jazz, and collected books, records, musical scores and model cars.

A virtuoso musician of professional quality, he performed in concert on the piano, harpsichord and fortepiano, a predecessor of the modern piano.

He was a knowledgeable historian of architecture and visited hundreds of historic buildings across Europe, recording them in detailed photographs.

Some of his photography was published in the book "Self, Cosmos, God" (1993).

Survivors include his wife of 33 years, Rajka Ungerer of Bethesda; a stepson, Dr. Daniel Kolak of Pomona, N.Y.; four grandchildren; and a brother.

Horst Friedrich Ungerer was considered a leading authority on international banking and financial policies. He died at 73.