Lynn Steen was one of the most respected and articulate voices in the field of mathematics, dedicating his career to advancing the way the discipline was taught and making it an appealing major for college students.

Steen had the belief that math should be a pump and not a filter, something that pushes people forward and does not weed them out, said Matthew Richey, professor of mathematics, statistics and computer science and one of Steen's colleagues at St. Olaf College in Northfield. He acted out that philosophy by getting his undergraduate students involved in research, a practice almost unheard of when he started it in the 1970s. He continued it throughout his 44-year career at the school. Steen's leadership allowed St. Olaf's math department to earn national acclaim and become of the top producers of undergraduate students who earn doctorate degrees in mathematical sciences.

"He envisioned a program that was open and exciting and attracted students," Richey said. "Historically math has been a laborious step-by-step process. He was more of an advocate of, 'Let's get to the good stuff right away.'"

Steen, 74, died of heart failure on June 21 at Abbott Northwestern Hospital in Minneapolis.

Born in Chicago, Steen grew up on Staten Island in New York. A nanny who was a math major engaged him in conversations on problem solving, and that piqued his interest in math, said Steen's wife, Mary, of Northfield.

Steen graduated from Luther College in Decorah, Iowa, in 1961 with majors in mathematics and physics. Four years later, he earned his doctoral degree in mathematics from the Massachusetts Institute of Technology at age 24. He started teaching at St. Olaf in 1965. Along with standard math classes, he taught an introduction to a computer science course called "Down the Rabbit Hole: the Mathematical Excursions of Lewis Carroll" and another in which he teamed with his wife, a St. Olaf English professor, to teach math and science students how to write essays that appeal to nontechnical audiences.

"That was an enjoyable course and the students got a lot out of it," Mary Steen said. "The course filled every year."

The course was discontinued as Lynn Steen drew deeper into research and was writing his own articles and papers on mathematics and curriculum that appeared in Scientific American, Science News and other academic journals. He wrote a report for the National Research Council on the challenges facing mathematics education in the United States and teamed up with St. Olaf students on the widely used reference book, "Counterexamples in Topology."

Steen was one of the founders of SciMathMN, an advocacy group seeking to improve how math and science are taught. On the national level, he was president of the Mathematical Association of America (MAA) and director of the Mathematical Sciences Education Board.

"Lynn's influence at the MAA is legendary; he probably did more to shape and focus it on its core missions than any other recent president," said Paul Zorn, another St. Olaf mathematics professor and former president of the MAA. "He wrote and spoke like an angel, clearly and forcefully, seeing right to the point in complicated settings."

In his later years, Steen was a special assistant to the provost at St. Olaf and served on numerous committees.

"He'd never tell you what to do. He helped you understand what you were trying to do," Richey said. "He made you believe that you came up with the right answer."

Besides his wife, Steen is survived by a brother, Richard, of New York City; two daughters, Margaret Steen, of Los Altos, Calif., and Catherine Wille, of Fergus Falls, Minn., and six grandchildren. Services have been held.