LOS ANGELES — Michael Crichton, the doctor-turned-author of bestselling thrillers such as “The Terminal Man” and “Jurassic Park” and a Hollywood writer and director whose credits include “Westworld” and “Coma,” has died. He was 66.

Crichton died in Los Angeles on Tuesday “after a courageous and private battle against cancer,” his family said in a statement.

For nearly four decades, the 6-foot-9 writer was a towering presence in the worlds of publishing and filmmaking.

“There was no one like Crichton, because he could both entertain and educate,” Lynn Nesbit, Crichton’s agent since the late ’60s, told the Los Angeles Times on Wednesday. “His brilliance was indisputable, and he had a grasp of so many subjects — from art to science to technology.

“I respected him so much intellectually and as a writer. I loved him. It’s like losing a very good friend as well as a client of so many years.”

Director Steven Spielberg in a statement Wednesday said, “Michael’s talent out-scaled even his own dinosaurs of ‘Jurassic Park.’ He was the greatest at blending science with big theatrical concepts, which is what gave credibility to dinosaurs again walking the earth.”

Spielberg, who was a new contract TV director at Universal in the early ’70s when he met Crichton and was assigned to show the writer around the lot, described him as “a gentle soul who reserved his flamboyant side for his novels.

“There is no one in the wings that will ever take his place.”

In the beginning

Crichton was still in Harvard Medical School when he wrote his first best-seller: “The Andromeda Strain,” a fast-paced scientifically and technologically detailed 1969 thriller about a team of scientists attempting to save mankind from a deadly microorganism brought to earth by a military satellite. It was made into a movie in 1971.

With his success at writing thrillers, Crichton abandoned medicine to become a full-time writer whose novels in the ’70s and ’80s included “The Terminal Man,” “The Great Train Robbery,” “Eaters of the Dead,” “Congo” and “Sphere.”

Crichton made his feature film directing debut in 1973 with “Westworld,” which he also wrote, about a fantasy theme park for wealthy vacationers whose fun is spoiled when malfunctioning androids turn deadly.

He directed five other movies in the ’70s and ’80s, including “Coma,” “The Great Train Robbery,” “Looker,” “Runaway” and “Physical Evidence.”

As a novelist, Crichton came back stronger than ever in the 1990s with bestsellers such as “Jurassic Park,” “Rising Sun,” “Disclosure,” “The Lost World,” “Airframe” and “Timeline.”

During the same decade, he co-wrote the screenplay for “Jurassic Park,” the 1993 Spielberg-directed blockbuster hit; and he co-wrote the screenplay for the 1996 action-thriller “Twister” with his fourth wife, actress Anne-Marie Martin, with whom he had a daughter, Taylor.

‘The Hit Man’

Crichton also created “ER,” the long-running NBC medical drama that debuted in 1994 and became the No. 1-rated series the next year.

Dubbed “The Hit Man” by Time magazine in a 1995 cover story chronicling his “golden touch,” Crichton had more than 100 million copies of his books in print at the time.

Indeed, the prolific writer who closely guarded his private life had become a dominant figure in popular culture.

Known for his intellectual curiosity, energy and drive, Crichton was a self-described workaholic.

“He works hard,” Anne-Marie Martin told Vanity Fair in 1994. “Toward the end of a book it’s like living with a body and Michael is somewhere else. Then, when the book’s finished, Michael comes back.”

When he wasn’t writing fiction, Crichton periodically turned to nonfiction, including “Jasper Johns,” a 1977 portrait of the artist; and the 1988 autobiographical book “Travels.”

He also wrote a book on information technology, “Electronic Life” (1983), formed a small software company in the early ’80s, designed a computer game and shared a 1995 Academy Award for technical achievement for pioneering computerized motion picture budgeting and scheduling.

The oldest of four children, Crichton was born Oct. 23, 1942, in Chicago and grew up in Roslyn, N.Y.

He developed wide interests at an early age, he later said, recalling his mother taking her children to plays, museums, movies and concerts several times a week.

Although he described his journalist father in his book “Travels” as “a first-rate son of a bitch,” he praised both parents for not setting limits on their children’s exploration.

“They were always saying, ‘You can do that.’ So I never had the feeling there was some area that I was incompetent in,” he told Vanity Fair in 1994.

Crichton enjoyed writing and, he later said, he wrote extensively from an early age.

The budding writer

In third grade, he wrote a nine-page play for a puppet show. At 13, he started submitting short stories to magazines, and he sold a travel article to the New York Times when he was 14.

He also covered high school sports for the local newspaper and later wrote for the Harvard Crimson.

Intending to become a writer, he entered Harvard as an English major in 1960. But after his professors criticized his writing style, he changed his major to anthropology.

After graduating summa cum laude in 1964, he spent a year on a fellowship as a visiting lecturer on anthropology at Cambridge University in England.

Returning home, he entered Harvard Medical School.

To pay his way through medical school, he began writing paperback thrillers under the pen names John Lange and Jeffery Hudson.

His 1968 medical thriller “A Case of Need,” written under his Jeffery Hudson pseudonym, won an Edgar Allan Poe Award from the Mystery Writers of America.

His 1969 novel “The Andromeda Strain” was his first book published under his own name.

He also co-wrote “Dealing: Or the Berkeley-to-Boston Forty-Brick Lost-Bag Blues,” a 1970 novel with his brother Douglas under the name Michael Douglas.

After receiving his medical degree in 1969, Crichton spent the next year as a postdoctoral fellow at the Salk Institute for Biological Studies in La Jolla, Calif.

But he continued to write, including “Five Patients: The Hospital Explained,” a 1970 nonfiction book that earned him a Writer of the Year award from the Association of American Medical Writers.

His most recent novel, “Next,” which dealt with genetics and the law, was published in 2006.

A complete list of surviving family members, who include his fifth wife, Sherri, and daughter Taylor, was not available.