A fully operational Apple computer that company co-founder Steve Jobs sold out of his parents' garage in 1976 for $600 will hit the auction block in December.

The machine is expected to sell for more than half a million dollars, Christie's said on Monday.

It could even hit a million dollars, after an auction last month saw the rare machine reach $905,000.

The machine is expected to sell for more than half a million dollars, Christie's said on Monday, and comes with documentation proving it was bought the the Jobs family home.

WHAT MAKES IT SO RARE? The Ricketts Apple-1 is fully operational, having been serviced and started by Apple-1 expert Corey Cohen in October 2014. Mr. Cohen ran the standard original software program, Microsoft BASIC, and also an original Apple-1 Star Trek game in order to test the machine. The computer will be sold with the cancelled check from the original garage purchase on July 27, 1976 made out to Apple Computer by Charles Ricketts for $600, which Ricketts later labeled as 'Purchased July 1976 from Steve Jobs in his parents' garage in Los Altos'. Advertisement

The so-called Ricketts Apple-1 Personal Computer, named after its original owner Charles Ricketts and being sold on Dec. 11, is the only known surviving Apple-1 documented as having been sold directly by Jobs, then just 21, to an individual from the Los Altos, California family home, Christie's said.

'It all started with the Apple-1 and with this particular machine,' said Andrew McVinish, Christie's director of decorative arts.

'When you see a child playing with an iPad or iPhone, not too many people know that it all started with the Apple-1,' he added. 'So to be able to own a machine that started the digital revolution is a very powerful attraction.'

The computer is being sold by Robert Luther, a Virginia collector who bought it in 2004 at a police auction of storage locker goods without knowing all the details of its history.

'I knew it had been sold from the garage of Steve Jobs in July of 1976, because I had the buyer's canceled check,' Luther wrote on a kickstarter page soliciting funding for a book on the machine's history.

'My computer had been purchased directly from Jobs, and based on the buyers address on the check, he lived four miles from Jobs.'

In 1999, the Ricketts Apple-1 was acquired by Bruce Waldack, an entrepreneur who had just sold his company, DigitalNation. Waldack eventually lost his fortune, left the country and died in 2007. The Ricketts Apple-1 was auctioned at a self-storage facility in Virginia, where Luther purchased it.

An Apple-1 expert serviced and started the computer, running the standard originalsoftware program, Microsoft BASIC, and an original Apple-1 Star Trek game to test it out, Christie's said.

THE ICONIC APPLE 1 Apple founders Steve Jobs and Steve Wozniak created the personal computer in 1976 and presented it at a Palo Alto computer club, but there were few takers at the time. Paul Terrell, owner of a retail chain called Byte Shop, placed an order for 50 of the machines and sold them for $666.66 (£420) retail - once Mr Wozniak and Mr Jobs agreed to assemble the circuit boards rather than offer them as kits. The pair then produced 150 more and sold them to friends and other vendors. Fewer than 50 original Apple 1s are believed to have survived, with only six known to be in working condition. The Apple 1 did not have a keyboard or monitor, meaning users had to supply their own. The Apple 1 did not have a keyboard or monitor, meaning users had to supply their own. Launched in July 1976, it was priced at $666.66 (£420) - reportedly because Apple founder Steve Wozniak liked repeating digits. It is not known how many were sold but by April 1977 the price had dropped to $475 (£300) It also had a tiny 8K memory - minuscule by today's standards. Launched in July 1976, it was priced at $666.66 (£420) - reportedly because Mr Wozniak liked repeating digits. Jobs sent them direct to buyers from the garage of his parents' house. It is not known how many were sold but by April 1977 the price had dropped to $475 (£300). The computer helped kick-start a technological revolution that brought affordable computers out of science labs and into people's homes. The Apple II was introduced in April 1977 with an integrated keyboard, sound, a plastic case, and eight internal expansion slots. By the time it was discontinued in October 1977, around 200 Apple 1s had been produced. It is thought that only 30 to 50 of the computers still exist today and there is rarely an opportunity to buy one. The computer helped kick-start a technological revolution that brought affordable computers out of science labs and into people's homes.The Apple II was introduced in April 1977 with an integrated keyboard, sound, a plastic case, and eight internal expansion slots Advertisement

The computer will be sold with the canceled check from the original garage purchase on July 27, 1976 made out to Apple Computer by Charles Ricketts for $600, which Ricketts later labeled as 'Purchased July 1976 from Steve Jobs in his parents' garage in Los Altos'.

The computer will be sold with the canceled check from the original garage purchase on July 27, 1976 made out to Apple Computer by Charles Ricketts for $600, which Ricketts later labeled as 'Purchased July 1976 from Steve Jobs in his parents' garage in Los Altos'.

A second canceled check for $193 from Aug. 5, 1976 is labeled 'Software NA Programmed by Steve Jobs August 1976.' The checks were used as evidence for the city of Los Altos to designate the Jobs family home on Crist Drive for eligibility for listing on the National Register of Historic Places.

Last month, the Henry Ford organization paid $905,000 at auction for one of the few remaining Apple-1 computers, which was more than twice the pre-sale estimate.

Fewer than 50 original Apple-1s are believed to be in existence of the few hundred originally produced.

Last month one of the few remaining examples of Apple's first pre-assembled computer, the Apple-1, was sold for $905,000 at an auction in New York, far outstripping expectations.

The relic, which sparked a revolution in home computing, is thought to be one of the first batch of 50 Apple-1 machines assembled by Apple co-founder Steve Wozniak in Steve Job's family garage in Los Altos, California in the summer of 1976.

Auction house Bonhams had said it expected to sell the machine, which was working as of September, for between $300,000 and $500,000 (£185,800 and £309,500)

One of the few remaining examples of Apple's first pre-assembled computer, the Apple 1, (pictured) has been sold for $905,000 at an auction in New York, far outstripping expectations

Auction house Bonhams had said it expected to sell the machine, which was working as of September, for between $300,000 and $500,000 (£185,800 and £309,500)

The identity of the buyer was not disclosed.

There were few buyers for the first Apples until Paul Terrell, owner of electronics retailer Byte Shop, placed an order for 50 and sold them for $666.66 each.

After that initial success, Jobs and Wozniak produced another 150 and sold them to friends and other vendors.