George Polya, 97, a professor emeritus of mathematics at Stanford University who was the author of "How to Solve It," one of the best-selling works in the history of mathematics, died Sept. 7 in Palo Alto, Calif., after a stroke.

"How to Solve It" was published in 1945. A popular paperback, it explored techniques of thought and logic that were the foundation of mathematic analysis. It has sold more than a million copies and was translated into 15 languages.

Dr. Polya was the author of more than 250 technical works. In pure mathematics, he did work in real and complex analysis, geometry, number theory and mathematical physics. His most important work was "Problems and Theorems in Analysis," which he co-authored with Gabor Szego. It was published in 1925.

Dr. Polya also worked in probability theory, which now includes "Polya criterion" in its vocabulary. In a 1921 paper, he introduced the term "random walk," now a branch of probability theory.

His name also is associated with research in complex function theory. His work in combinatorics contains the "Polya enumeration theorem" and the Polya Prize in Combinatorial Theory and Its Applications given by the Society for Industrial and Applied Mathematics.

Dr. Polya was a 1963 recipient of the distinguished service award of the Mathematical Association of America. The award said, "He has given a new dimension to problem solving by emphasizing the organic building up of elementary steps into a complex proof, and conversely, the decomposition of mathematical invention into smaller steps."

Dr. Polya was a native of Budapest and received his doctorate in mathematics at the University of Budapest in 1912. He taught at the University of Gottingen, the University of Paris, and the Swiss Institute of Technology, before coming to this country and joining the Stanford faculty in 1940.

After retiring from full-time teaching in 1953, he devoted attention to the education and training of teachers of mathematics. He said that mathematics was interesting, but often badly taught. He taught his last class at Stanford in 1978.

Survivors include his wife of 67 years, the former Stella Vera Weber.