Leithold dies at age 80.

The first time I got acquainted with Leithold's Calculus 7th edition book was during my 4th year in Pisay. I never got to use it often then. Mrs. Egasan, my feisty calculus teacher, always brought sheets and sheets of manila paper to show us, summarizing eveything that Leithold had to say in the book. Besides, we didn't want to bring the 100-ton book everyday in class.

I realized in college how important that 100-ton book was. Mrs. Egasan was, and from what I hear, remains as, the most fascinating teacher a person can have in high school, but not even she can reduce Leithold's teachings to a finite number of manila paper sheets. In college, I discovered the wealth of mathematical information that book contained. I didn't use the book only for the four semesters that I had calculus; I used it until the very end of my college education. The content of that book encompassed almost every possible mathematical subject known to mankind that it was impossible not to refer to it every now and then. That's how amazing it was.

It is unfortunate, then, to hear this news. Louis Leithold died at the age of 80. I never thought I would be disturbed by such incident, but I am. I feel a great loss has taken place. Calculus would never be the same without him.

Here is the news, taken from news.yahoo.com.

LOS ANGELES - 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.