Today is a sad day in the tech world. 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, iPhone and iPad, has died after an eight-year battle with pancreatic cancer. He was 56. Without revealing a cause of death, Apple issued this statement: "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." In a statement on the the company's Web site, new CEO Tim Cook writes: "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." In 2004, he announced to his employees that he was being treated for pancreatic cancer. In 209, he had a secret liver transplant during a six-month medical leave of absence from Apple. He took another medical leave in January this year. He is survived by his wife of 20 years, Laurene, and four children.