The Pursuit of Knowledge

Amir D. Aczel, a science writer who took readers on a mathematical mystery tour in “Fermat’s Last Theorem,” his account of how a famous 300-year-old problem in number theory was finally solved in the 1990s, and went on to write more than a dozen popular books on intriguing scientific ideas and discoveries, died on Nov. 26 in Nîmes, in the south of France. He was 65.

The cause was cancer, his wife, Debra Gross Aczel, said.

Mr. Aczel (pronounced ahk-ZEL) was teaching statistics at Bentley College in Waltham, Mass., and writing college textbooks when one of the great scientific cliffhangers of all time reached a resolution.

In a marginal note written in 1637, the French mathematician Pierre de Fermat had claimed to know the answer to an equation that seemed to admit of no solution, but could not write it down because there was no room on the page of the book he was annotating. In 1994 Peter Wiles, a British mathematician at Princeton, arrived at the elusive solution, which was published in the journal Annals of Mathematics the following year.

Mr. Aczel saw in Mr. Wiles’s feat a wonderful scientific tale, and he proceeded to tell it in “Fermat’s Last Theorem: Unlocking the Secret of an Ancient Mathematical Problem,” published in 1996. “What is interesting about Fermat’s Last Theorem is that it spans mathematical history from the dawn of civilization to our own time,” he wrote. “And the theorem’s ultimate solution also spans the breadth of mathematics.”

In a review for The New York Times, Richard Bernstein called the book “a tale of buried treasure, the treasure here being immaterial, intellectual, of no practical benefit, but rooted in the pleasure of pure knowledge.”

Mr. Aczel parlayed the success of “Fermat’s Last Theorem” into books on the discovery of the compass, the probability of life on other planets, the discovery of the Higgs boson (sometimes referred to as the God particle) and the history of the numeral zero.

Amir Dan Aczel was born on Nov. 6, 1950, in Haifa, Israel. His father piloted a Mediterranean cruise ship, and he spent his childhood on board, sailing from one port of call to the next. Monte Carlo exerted a special fascination.

“There I saw magical, ornate numbers on the roulette tables: half red and half black, and one special round circle of a number alone in green,” he wrote in Time magazine in May, describing his surreptitious visits to the casino. “Its image was etched in my mind, and in part led me to pursue a career in numbers as a mathematician and statistician.”

After receiving his bachelor’s and master’s degrees in mathematics from the University of California, Berkeley, he earned a doctorate in decision sciences, a field embracing statistics and operations management, from the business school at the University of Oregon in 1982.

While teaching at the University of Alaska, he complained to a traveling textbook salesman that no one had written a good book on statistics, to which the salesman responded, “Write one.” The result was “Complete Business Statistics,” published in 1989. It went through eight editions and spawned several successors.

A brutal audit of his 1989 tax return by the Internal Revenue Service, which questioned the deductions on his textbook work, inspired “How to Beat the I.R.S. at Its Own Game: Strategies to Avoid — and Fight — an Audit” (1996). Mr. Aczel analyzed more than 1,289 actual tax returns, half of which had been audited and half not, to identify the red flags most likely to provoke an audit. It sold quite well in the months leading up to April 15 and convinced its author that there was an exciting world beyond textbooks.

By seeking out scientific topics with a colorful narrative behind them, Mr. Aczel developed a cottage industry writing books aimed at the general reader curious about such matters as probability theory, the pendulum and the existence of God. His many books include “The Mystery of the Aleph: Mathematics, the Kabbalah, and the Search for Infinity,” “The Riddle of the Compass: The Invention That Changed the World” and “Entanglement: The Greatest Mystery in Physics.”

In addition to his wife, Mr. Aczel, who had recently moved to Uzès, France, is survived by a daughter, Miriam Rose Aczel.

Mr. Aczel’s most recent book, “Finding Zero: A Mathematician’s Odyssey to Uncover the Origins of Numbers,” published in January, took him to Cambodia in search of a stone slab from the seventh century thought to have been plundered during the rule of Khmer Rouge. Its inscriptions include the number 605, a reference to the number of years that had passed since the beginning of the Chaka era in A.D. 78. This, the first known use of zero, has strongly suggested to scholars that zero originated in Asia and was carried to the Middle East by Arab traders. Mr. Aczel tracked the stone down near Angkor Wat.

“To me it represents something immense because it’s the human understanding of the concept of nothingness, which is a hard concept to accept,” he told Scientific American in 2014. “Why would nothing be a number? If it’s nothing, then it shouldn’t be number, but the nothing is really very important.”