Steve Jobs has died after a long struggle with cancer.

CUPERTINO, Calif. — Steve Jobs, the Apple founder and former CEO who invented and masterfully marketed ever-sleeker gadgets that transformed everyday technology, from the personal computer to the iPod and iPhone, has died. He was 56.

Apple announced his death without giving a specific cause. He had been battling pancreatic cancer.
“We are deeply saddened to announce that Steve Jobs passed away today,” the company said in a brief statement. “Steve’s brilliance, passion and energy were the source of countless innovations that enrich and improve all of our lives. The world is immeasurably better because of Steve.”

Jobs had battled cancer in 2004 and underwent a liver transplant in 2009 after taking a leave of absence for unspecified health problems. He took another leave of absence in January — his third since his health problems began — before resigning as CEO six weeks ago. Jobs became Apple’s chairman and handed the CEO job over to his hand-picked successor, Tim Cook.

By the time he turned the reins of the company over to Cook, Jobs had become one of the business world’s greatest comeback kids.

The company he founded, was fired from and then returned to had gone from also-ran to technology industry leader. Under Jobs’ intensely detail-oriented leadership, Apple created several iconic products, including the iPod, iPhone and iPad, that have changed the face of consumer technology forever.

In the process, he transformed Apple into one of the nation’s most valuable companies and himself into one of the world’s richest men.

Just Wednesday the company released a new version of the iPhone, the first such major product announcement in years that didn’t involve Jobs.

Cancer

Jobs’ family issued a statement: “Steve died peacefully today surrounded by his family. … We are grateful for the support and kindness of those who share our feelings for Steve. We know many of you will mourn with us, and we ask that you respect our privacy during our time of grief.”

Cook sent a statement to employees that in part read: “Apple has lost a visionary and creative genius, and the world has lost an amazing human being. Those of us who have been fortunate enough to know and work with Steve have lost a dear friend and an inspiring mentor. Steve leaves behind a company that only he could have built, and his spirit will forever be the foundation of Apple.”

Microsoft co-founder and sometimes Jobs rival Bill Gates tweeted: “Melinda and I extend our sincere condolences to Steve Jobs’ family & friends. The world rarely sees someone who made such a profound impact.”

Medical experts expressed sadness but not surprise at Jobs’ death, which followed treatment for a neuroendocrine pancreatic tumor, first diagnosed in 2004, a liver transplant in 2009, and then, likely, the recurrence of disease earlier this year.

“He not only had the cancer, he was battling the immune suppression after the liver transplant,” noted Dr. Timothy Donahue of the UCLA Center for Pancreatic Disease in Los Angeles.

In patients who have liver transplants after such tumors, the median survival rate is typically about two years.

“It’s even more remarkable he was able to do what he did,” Donahue said.

Job’s ability to continue working as long as he did likely was a result of his personal constitution, his dedication to his work and the care of doctors who could help him receive specialized therapies, said Dr. Jeffrey I. Mechanick, an endocrinologist with Mount Sinai Medical Center in New York.

In the end, however, even the most dedicated patients have to bend to the disease, he added.

“Sometimes, they just have to say, ‘I’m going to spend time with my family,’” Mechanick said.

Beginnings

Steven Paul Jobs was born Feb. 24, 1955, in San Francisco to Joanne Simpson, then an unmarried graduate student, and Abdulfattah Jandali, a student from Syria. Simpson gave Jobs up for adoption, though she married Jandali and a few years later had a second child with him, Mona Simpson, who became a novelist.

Steven was adopted by Clara and Paul Jobs of Los Altos, California, a working-class couple who nurtured his early interest in electronics. He saw his first computer terminal at NASA’s Ames Research Center when he was around 11 and landed a summer job at Hewlett-Packard before he had finished high school.

Jobs is survived by his biological mother; sister Mona Simpson; Lisa Brennan-Jobs, his daughter by onetime girlfriend Chrisann Brennan; wife Laurene; and their three children, Erin, Reed and Eve.

Jobs enrolled in Reed College in Portland, Ore., in 1972 but dropped out after six months.

“All of my working-class parents’ savings were being spent on my college tuition. After six months, I couldn’t see the value in it,” he said at a Stanford University commencement address in 2005. “I had no idea what I wanted to do with my life and no idea how college was going to help me figure it out.”

When he returned to California in 1974, Jobs worked for video game maker Atari and attended meetings of the Homebrew Computer Club — a group of computer hobbyists — with Steve Wozniak, a high school friend who was a few years older.

Wozniak’s homemade computer drew attention from other enthusiasts, but Jobs saw its potential far beyond the geeky hobbyists of the time. The pair started Apple Computer Inc. in Jobs’ parents’ garage in 1976. According to Wozniak, Jobs suggested the name after visiting an “apple orchard” that Wozniak said was actually a commune.

Their first creation was the Apple I — essentially, the guts of a computer without a case, keyboard or monitor.

The Apple II, which hit the market in 1977, was their first machine for the masses. It became so popular that Jobs was worth $100 million by age 25.

Talent for re-invention

During a 1979 visit to the Xerox Palo Alto Research Center, Jobs again spotted mass potential in a niche invention: a computer that allowed people to control computers with the click of a mouse, not typed commands. He returned to Apple and ordered the team to copy what he had seen.

It foreshadowed a propensity to take other people’s concepts, improve on them and spin them into wildly successful products. Under Jobs, Apple didn’t invent computers, digital music players or smartphones — it reinvented them for people who didn’t want to learn computer programming or negotiate the technical hassles of keeping their gadgets working.

“We have always been shameless about stealing great ideas,” Jobs said in an interview for the 1996 PBS series “Triumph of the Nerds.”

The engineers responded with two computers. The pricier Lisa — the same name as his daughter — launched to a cool reception in 1983. The less-expensive Macintosh, named for an employee’s favorite apple, exploded onto the scene in 1984.

The Mac was heralded by an epic Super Bowl commercial that referenced George Orwell’s “1984″ and captured Apple’s iconoclastic style. In the ad, expressionless drones marched through dark halls to an auditorium where a Big Brother-like figure lectures on a big screen. A woman in a bright track uniform burst into the hall and launched a hammer into the screen, which exploded, stunning the drones, as a narrator announced the arrival of the Mac.

There were early stumbles at Apple. Jobs clashed with colleagues and even the CEO he had hired away from Pepsi, John Sculley. And after an initial spike, Mac sales slowed, in part because few programs had been written for it.

With Apple’s stock price sinking, conflicts between Jobs and Sculley mounted. Sculley won over the board in 1985 and pushed Jobs out of his day-to-day role leading the Macintosh team. Jobs resigned his post as chairman of the board and left Apple within months.

“What had been the focus of my entire adult life was gone, and it was devastating,” Jobs said in his Stanford speech.

“I didn’t see it then, but it turned out that getting fired from Apple was the best thing that could have ever happened to me. The heaviness of being successful was replaced by the lightness of being a beginner again, less sure about everything. It freed me to enter one of the most creative periods of my life.”

He got into two other companies: Next, a computer maker, and Pixar, a computer-animation studio that he bought from George Lucas for $10 million.

Pixar, ultimately the more successful venture, seemed at first a bottomless money pit. Then in 1995 came “Toy Story,” the first computer-animated full-length feature. Jobs used its success to negotiate a sweeter deal with Disney for Pixar’s next two films, “A Bug’s Life” and “Toy Story 2.” In 2006, Jobs sold Pixar to The Walt Disney Co. for $7.4 billion in stock, making him Disney’s largest individual shareholder and securing a seat on the board.

With Next, Jobs came up with a cube-shaped computer. He was said to be obsessive about the tiniest details, insisting on design perfection even for the machine’s guts. The machine cost a pricey $6,500 to $10,000, and he never managed to spark much demand for it.

Ultimately, he shifted the focus to software — a move that paid off later when Apple bought Next for its operating system technology, the basis for the software still used in Mac computers.

By 1996, when Apple bought Next, Apple was in dire financial straits. It had lost more than $800 million in a year, dragged its heels in licensing Mac software for other computers and surrendered most of its market share to PCs that ran Windows. Jobs’ personal ethos — a natural food lover who embraced Buddhism and New Age philosophy — was closely linked to the public persona he shaped for Apple. Apple itself became a statement against the commoditization of technology — a cynical view, to be sure, from a company whose computers can cost three or more times as much as those of its rivals.

For technology lovers, buying Apple products has meant gaining entrance to an exclusive club. At the top was a complicated and contradictory figure who was endlessly fascinating — even to his detractors, of which Jobs had many.

Jobs was a hero to techno-geeks and a villain to partners he bullied and to workers whose projects he unceremoniously killed or claimed as his own.

Unauthorized biographer Alan Deutschman described him as “deeply moody and maddeningly erratic.” In his personal life, Jobs denied for two years that he was the father of Lisa, the baby born to his longtime girlfriend Chrisann Brennan in 1978.

Charismatic

Few seemed immune to Jobs’ charisma and will. He could adeptly convince those in his presence of just about anything — even if they disagreed again when he left the room and his magic wore off.

“He always has an aura around his persona,” said Bajarin, who met Jobs several times while covering the company for more than 20 years as a Creative Strategies analyst. “When you talk to him, you know you’re really talking to a brilliant mind.”

But Bajarin also remembers Jobs lashing out with profanity at an employee who interrupted their meeting. Jobs, the perfectionist, demanded greatness from everyone at Apple.

Jobs valued his privacy, but some details of his romantic and family life have been uncovered. In the early 1980s, Jobs dated the folk singer Joan Baez, according to Deutschman.

In 1989, Jobs spoke at Stanford’s graduate business school and met his wife, Laurene Powell, who was then a student.

When she became pregnant, Jobs at first refused to marry her. It was a near-repeat of what had happened more than a decade earlier with then-girlfriend Brennan, Deutschman said, but eventually Jobs relented.

Jobs started looking for his biological family in his teens, according to an interview he gave to The New York Times in 1997. He found his biological sister when he was 27. They became friends, and through her Jobs met his biological mother. Few details of those relationships have been made public.

But the extent of Apple secrecy didn’t become clear until Jobs revealed in 2004 that he had been diagonosed with — and “cured” of — a rare form of operable pancreatic cancer called an islet cell neuroendocrine tumor. The company had sat on the news of his diagnosis for nine months while Jobs tried trumping the disease with a special diet, Fortune magazine reported in 2008.

In the years after his cancer was revealed, rumors about Jobs’ health would spark runs on Apple stock as investors worried the company, with no clear succession plan, would fall apart without him. Apple did little to ease those concerns. It kept the state of Jobs’ health a secret for as long as it could, then disclosed vague details when, in early 2009, it became clear he was again ill.

Jobs took a half-year medical leave of absence starting in January 2009, during which he had a liver transplant. Apple did not disclose the procedure at the time; two months later, The Wall Street Journal reported the fact and a doctor at the transplant hospital confirmed it.

In January 2011, Jobs announced another medical leave, his third, with no set duration. He returned to the spotlight briefly in March to personally unveil a second-generation iPad and again in June, when he showed off Apple’s iCloud music synching service. At both events, he looked frail in his signature jeans and mock turtleneck.

Less than three months later, Jobs resigned as CEO. In a letter addressed to Apple’s board and the “Apple community” Jobs said he “always said if there ever came a day when I could no longer meet my duties and expectations as Apple’s CEO, I would be the first to let you know. Unfortunately, that day has come.”

“Remembering that I’ll be dead soon is the most important tool I’ve ever encountered to help me make the big choices in life,” he said in the 2005 Stanford speech. “Because almost everything — all external expectations, all pride, all fear of embarrassment or failure — these things just fall away in the face of death, leaving only what is truly important.”

Associated Press and Reuters contributed to this report.