Steve Jobs has quite possibly found his match in Tim Cook when it comes to his work ethic and clear passion for Apple.
Cook is awake at 4.30am most mornings sending emails and preparing for the day ahead. He has even been known to hold Sunday night staff meetings by telephone to prepare for the coming week.
“Tim may not be as charismatic as Steve but he commands huge respect,” said Carolina Milanesi, an analyst at Gartner. “He's very grounded and is on top of the products."
On paper, Cook fits the bill. But he is still not the notorious iGod. Jobs - often found pacing the stage at technology events attired in signature jeans and black turtleneck - has an unrivalled ability to create an air of excitement and suspense certain to entice the biggest technophobe. He is Apple’s most effective marketing tool.
"Like the Wizard of Oz, Jobs tries his best to hide behind a curtain, keeping a tight rein on media access and dealing harshly with friends who say too much to biographers," says one San Francisco reporter.
Cook – or anyone else for that matter – is unlikely to be able to mirror Jobs’s presence. However, the industry view of Cook is as an intelligent and capable leader. The consensus is that, under Cook, Apple is in good hands.
He is credited with creating a more efficient, productive operation at Apple. Cook pulled Apple out of manufacturing by closing factories and warehouses around the world.
This helped the company reduce inventory levels and streamline its supply chain, dramatically increasing margins. His appointment as chief operating officer at Apple came in 2005.
An Alabama native, Cook was hired by Steve Jobs in 1998 following Jobs’ return to Apple in 1997 to oversee the manufacturing of Apple computers.
He had previously worked at Compaq and IBM. Despite speculation over the years that Cook could be lured to a competitor - with reports linking hime with Motorola and Dell - Cook has remained a loyal member of Jobs's close-knit team.
He has built a trusting relationship with Jobs and has long played a key, behind-the-scenes role in steering Apple, alongside the tech giant’s colourful founder.
In August 2004, Cook ran Apple for two months while Jobs recuperated from surgery to remove a cancerous tumour from his pancreas. In 2009 Cook stood in as chief executive while Jobs took a leave of absence for a liver transplant.
It emerged earlier this month that Cook was handed compensation worth $59.1m (€44m) in the last financial year, including a $5m cash bonus and $52.3m in stock options.
He has sold more than $100m of his stock options since joining Apple. However, despite his wealth, the son of a shipyard worker rents his house in Palo Alto, California.
The latest news of Jobs’s medical leave comes as Apple said earlier this month that there would be a vote at its annual general meeting in February on a proposal from the Central Laborers' Pension Fund that Apple should have a public succession plan. Apple has urged investors to vote against it.