Calculus textbook author dies at 80

LOS ANGELES, California (AP) -- Louis Leithold, who wrote one of the most widely used calculus textbooks and helped change the way the subject is taught, has died. He was 80.

Leithold was found dead April 29 at his Los Angeles home by the parent of a worried student. The coroner's office said he died of natural causes.

Leithold wrote "The Calculus," which became a standard text and was credited with changing the way the subject is studied. The book, first published in 1968, is widely used in high schools and universities and is in its seventh printing.

He was 72 when he declined to retire and instead launched a calculus program at Malibu High School after being approached by a teacher.

"He inspired you to do mathematics. His face would just light up," said student Matthew Mesher, 17.

Among the many educators he influenced was Jaime Escalante, whose success teaching calculus to poor, largely minority students in East Los Angeles was chronicled in the 1988 film "Stand and Deliver."

"I called him my adviser," Escalante said Saturday. "He was one of the great mathematicians. His book had beautiful problems. It made us believe that anybody could do calculus."

Leithold held a doctorate in math and taught at numerous schools during his long career, including California State University at Los Angeles, the University of Southern California, Pepperdine University and the Open University of Great Britain.